FR2730937A1 - Single-use syringe with automatic needle retraction - Google Patents

Abstract

The syringe consists of a body (6) and a needle holder (2) which has a needle (1) stuck in it by a paste adhesive. The inner end of the holder has four claws (8b) which permit the passage of a soft rubber plunger (7) on the end of the piston and a stop collar. The syringe body, needle holder and piston are all made from the same plastic material. During operation the piston travels past the claws at the end of its stroke, and when it is withdrawn it retracts the needle into the body so it cannot be re-used.

Description

DESCRIPTION
The present invention relates to an intravenous syringe device consisting of a system which renders the syringe unusable more than once, with two safety devices and the needle of which is retractable in the syringe block.

Traditionally syringes do not have in a combined manner both a retractable needle system, a single use and a manufacturing cost equal to that of an unprotected syringe. This combined lack of security tends to increase the risk of spreading communicable diseases, types H. I. V, Hepatitis ..

We find in the trade several methods of protection of these risks. First of all, needle and syringe collectors, needle protectors, disposable syringes. However, all of these systems do not offer security which responds both to the disappearance of the risk by accidental injections and to the impossibility of reusing the syringe and the needle.

The device according to the invention makes it possible to remedy the spread of infectious diseases by a simple process.

According to a first characteristic, the device comprises a needle fixed to a sole block by an adhesive paste, which corresponds to a first novelty. This needle comes out of lmm in the interior of the sole block, which is a second novelty. This sole block is itself installed in the cylinder head of the syringe. They are linked together by a rubber seal placed in a groove in the cylinder head. This grooving is of a depth less than the thickness of the joint. the sole block penetrates the cylinder head by a rotary adjustment and compresses the seal, making the system watertight
According to the invention, this sole block has four excavations forming locking clips.

When the piston, sometimes called the syringe pump, is pushed to the end by the user, (drug addicts, nurses, or individuals) the suction cup at the piston head impaled on the inner point of the needle protruding , as we saw from 1 mm. The system obliges the user to lead the piston to the end of the race (reflex of the addict not to lose anything of the liquid, medical necessity of the nurse). This suction cup will then be permanently destroyed and a second use will be impossible.

At the same time the clips will lock the sole of the piston in the pushed position.

When the user wants to return the piston to the position of use, it necessarily drives the needle, sole block and piston assembly locked together in the cylinder head of the syringe.

Variant A depending on manufacturing requirements.

 It is possible to replace the compressible rubber seal installed in the cylinder head with an external circular lug integrated by molding in the sole block, as of manufacture fg 5.

Variant B according to manufacturing requirements.

 I1 is also possible to replace the in, t clips of the sole block with a circular inner lug slightly offset from the outer lug defined in the previous paragraph. so as to allow it to disappear into the cylinder head housing, when the FG 6 piston passes.

According to the particular embodiments - the thickness of the claw clips (8d) can be increased as well as the thickness of the sole block in order to produce greater resistance to locking.

- the needle (1) can be fixed in the sole block without adhesive paste, but directly during manufacture.

- the seal (4) can be replaced by a roughened surface on the cylinder head and the sole block.

The seal (4) can be replaced by a chamfered circular lug (12), inwards.

- The clip-on claws can be replaced by a circular lug (14) chamfered inside the sole block.

- The cylinder head can have a wider grooving which allows the evacuation of the circular lug during the passage of the piston.

- The lugs (12) and (14) of variants A and B have a chamfer as well as the groove of the cylinder head (6), in order to facilitate removal.

- All the descriptions and variants are given by way of example, however the device adapts to any other dimension of syringes, to any other quantity of dosage.

The figurations 1; 2.3. 4 show in section the syringe according to the invention.

Figure (5) shows the invention according to the provisions of variant A.

Figure (6) shows the invention according to the provisions of variant B.

With reference to the drawings in Figures 1.2. 3. 4. the syringe has a needle marked (1), protruding by 1 mm towards the inside of the block-sole (2), fg 2, is made integral by an adhesive paste (3) the density of the plastic of the block- sole is less important than that of the cylinder head.

The sole block penetrates into the cylinder head over a length of 14 mm, the thickness of the walls is 3/10 of mm, it is likely that a study could reduce this thickness to 2.5 / 10 of mm.

The sole block is made integral with the cylinder head (6) by a rubber seal (4), fg 1.

While the sole block (2) penetrates the cylinder head (6) by a "rotating" adjustment. The latex seal (4) fits into a groove in the cylinder head (6), the width of this groove is 2 mm and the depth of 3/10 of mm. The thickness of the seal is 3, 5/10 of a mm consequently this seal undergoes a compression of 1/10 of a mm, during the positioning of the sole block in the cylinder head (6). The sealing of the system is made possible, as well as the solidarity of the sole block and the cylinder head.

Furthermore, in the sole block (2), four indentations forming clip claws (8d) were made during manufacture on the lower and inner part of the sole block (6), fg 1.

They (8d) have the function of allowing the suction cup (10) placed at the end of the pump piston (5) to pass. On the other hand, they prevent the return of the same piston and of the suction cup once the injection has been made. The suction cup (10) in this injection position impaled on the needle, protruding 1 mm in the sole block.

The seal is made permanently unusable by the tearing of the suction cup (10) fg 3.

The clip claws enclose the piston head (5), fg 2, and make the piston, the sole block and the needle integral, forming a lock during the liquid injection position, fg 2.

The cylinder head (6) has another characteristic, the grooving which allows the installation of the seal (4). The rigid plastic syringe cylinder head with a wall thickness of 1 mm can, according to some variant, be manufactured with a thickness of 8/10 mm.

The functions of the cylinder head are multiple, they are characterized in the context of the invention by the need to guide the piston (7), but also to serve as a reservoir for the product to be injected, to control the dosage by graduations on the body of the cylinder head, to visualize the evacuation of air bubbles through the transparency of the plastic.

The piston (7) has several specificities, first of all the piston head, as we have seen, is equipped with a traditional rubber suction cup (10).

A reduction in diameter is made on this flange (8c) and on 15 mm from the top of the suction cup (10), to the second flange of the piston (8b) so that it can be housed in the sole block .

The suction cup (10) adapts by compression to the fine difference in diameter between that of the cylinder head and that of the sole block. The second collar of the marked piston (8b) has the dimension of the internal diameter of the cylinder head and abuts on the sole block, FG 2, the syringe becomes unusable.

Description of the retraction position of the needle in order to protect us from accidental punctures and to ensure the triggering of a second safety device.

In Figure 3, we see that the sole block (2) is secured to the cylinder head by the seal (4), and the piston is found retained by the claws (8d). The adhesion of the sole block (2) in the cylinder head is due to the compressed seal (4).

If the user pulls on the piston (7) which is locked by the claws (8d), it is the piston assembly, needle sole block which will escape from the seal (4).

On the piston, the adhesion formed by the seal (4) is more fragile than the grip of the claws of the sole block.

Thus, the needle is found housed in the body of the bolt, which represents protection against accidental risks, and moreover the sole block having escaped from the joint this represents a second security, the device is then destroyed.

The ear cups (8) are in the same density of plastic as the sole block. They come to be fitted in a tight fit on the outside of the cylinder head
Because of this adjustment, there is a natural bulge (8a) forming a stop at the part (8b) of the piston, preventing it from coming out of the cylinder head, FG 4.

The end of the piston has a base in pusher sole of round shape. The piston body is made up of two cross section angles (7).

According to demand, this manufacture is a device which adapts to all the dimensions of syringes.

According to variant A, fg 5.

The sole block has integrated a circular lug which replaces the latex seal (4). By its shape, the circular lug allows the movement of the sole block (2) towards the inside of the cylinder head and prevents it from coming out towards outside. The retraction movement of the sole block with the piston (7) inwards is made possible by the elasticity of the design of this sole block and has a chamfer made both on the lug and in the groove of the breech.
According to variant B figure 6
The sole block (2) has two circular pins, (12), (14), one which replaces the rubber seal, and the other, the claws (8a). The groove in the cylinder head is wider than necessary for the movement, so that this design allows the lug (14) for replacing the claw clips (8a) to disappear in the groove of the cylinder head when the piston comes lodge in the soleplate causing the circular lug (14) to be clamped onto the piston head (7). Thus, it keeps the piston block integral with the sole block. When the user wishes, he pulls on the piston, which necessarily brings the sole block with him. Indeed, the adhesion which links the sole block and the cylinder head is of less mechanical resistance than that which links the piston and the sole block. The ejection movement is favored by the chamfers provided on the lug (12) and the grooving (6). This variant seems to have the many qualities of reliability and manufacturing, while providing a reduced cost price.

Claims (1)

CLAIM 1 Device for single-use injection syringe with retraction of the needle, and destruction of the capacity for accidental use. Characterized in that it comprises a syringe consisting of a syringe body (6) retaining immobilized a sole block (2) by a suitable means, to this latter is fixed to a needle (1) in the sole block (2) by an adhesion means (3); the sole block (2) provided at its internal end with 4 clip claws (8b) which allow the passage of the piston (7), itself constituted by a soft rubber suction cup (10) and a flange-stop ( 8). At the end of the syringe body, a manufacturing blister (8d) appears. CLAIM 2 - Device according to claim 1 characterized in that the parts, (6) of the syringe body, (2) of the sole block and (7) of the piston are all of the same plastic.  CLAIM 3 - Device according to claim 1 and 2 characterized in that the needle is fixed in a non-removable manner by bonding an adhesive paste, or mounted hot (expansion) and blocked in the sole block (2), during cooling or by adhesive paste joint. CLAIM 4 - Device according to claim 1 characterized in that the means serving to immobilize the sole block (2) and the syringe body (6) consists of a seal (4), or by a striated surface in opposition one on the other, or by a circular lug (12) of the same material as the syringe body (6) provided with a chamfer on the circular edge. CLAIM 5 - Device according to claim 1 and 4 characterized in that it has 4 claws clips (8d) whose distribution is located at an equal distance between them and whose shape promotes the passage of the piston (7) whose penetration is permitted by an access chamfer and by the deformation of the sole block (2), left by the adhesion means between the sole block (2) and the body (6). CLAIM 6 - Device according to claims 1 and 2 characterized in that a circular grooving has been machined in the cylinder head (6) in the case of immobilization by circular lug (14), (12).