WO1995027524A1

WO1995027524A1 - Single-use syringe with retractable needle

Info

Publication number: WO1995027524A1
Application number: PCT/FR1995/000458
Authority: WO
Inventors: Patrice Elfandi; Charles Merchin
Original assignee: Patrice Elfandi; Charles Merchin
Priority date: 1994-04-11
Filing date: 1995-04-11
Publication date: 1995-10-19
Also published as: FR2718358B1; FR2718358A1

Abstract

Syringe comprising a barrel (100), a plunger (200) provided with a shaft (202) and head (206) mounted slidingly in said body. A tip holder (212) contains a fluid passage for receiving a standard needle tip. Retaining means (112, 219c) between the body and the end piece holder are unlocked by the plunger head being drawn close as the medication is injected and means (209, 222) are provided between the plunger and tip holder for engaging with one another during said movement. In order to drive the carrier-tip and the needle within the barrel, the syringe includes a single part (210) forming the tip holder, retaining means and engaging means, and includes flexible elements which, when biased by the head, unlock the retaining means and enable the engaging means (209, 222) to engage. According to the invention, the syringe includes flexible sealing means (214) forming a single piece with said part, said retaining means and engaging means consisting of flexible tabs (218) capable of being drawn together.

Description

SINGLE-USE SYRINGE WITH RETRACTABLE NEEDLE

The present invention relates generally to a syringe, of the type comprising a generally cylindrical syringe body, a plunger provided with a rod and a head slidably mounted in the syringe body, a tip-holder element housing a passage fluid and intended to receive a standard needle tip, retaining means provided between the syringe body and the tip-holder element, said retaining means being able to be unlocked under the action of a movement of movement of the piston head at the end of injection, hooking means provided between the piston head and the bit-holder element to ensure mutual hooking during said approaching movement, and then allow the traction of the carrier element tip and its needle inside the syringe body, the syringe comprising a single piece constituting the tip-holder element, the retaining means, the hooking means, and this piece comprises ant flexible arrangements whose sole request by the piston head during the movement of movement allows both the unlocking of the retaining means and the attachment of the attachment means.

Such a syringe is known in particular from documents OA-91 07198. It allows, by sheltering the needle in the syringe body at the end of the injection, to avoid any transmission of disease by accidental injection. by caregivers or by chance.

This type of known syringe, however, has a number of drawbacks. First of all, it has hooking means which leave a large empty space between them, leaving a large amount of residual liquid remaining after the injection, and which may prove to be insufficiently robust for drawing the syringe inside. of the syringe body by resisting friction. 7524 PCI7FR95 / 00458

In addition, given the configuration of the end of the syringe body and of the part, this type of known syringe can give rise to the presence of air bubbles which cannot be eliminated in the liquid to be injected. Indeed, this configuration constitutes a trap for air bubbles.

Finally, this type of known syringe prevents leakage of the liquid to be injected by simple complementarity of surfaces, which can prove to be ineffective. The present invention aims to overcome these drawbacks of the prior art, and more particularly to propose a syringe of the type mentioned in the introduction, in which the amount of residual liquid is minimized, which has good sealing, and which allows good quality hooking for pulling the needle inside the syringe body.

The syringe according to the invention is remarkable in that it comprises flexible sealing means produced in one piece with the single piece, and in that the retaining means and the hooking means consist of a set flexible lugs capable of being intimately brought closer to one another when the retaining means are unlocked and the hooking means are hooked. Other aspects, aims and advantages of the present invention will appear better on reading the following detailed description of a preferred embodiment thereof, given by way of non-limiting example and made with reference to the accompanying drawings, in which: FIG. 1 is an overall view in longitudinal section of a syringe according to the invention, FIGS. 2a and 2b are views in longitudinal section of detail parts of the syringe in FIG. 1, in two positions different, Figure 3 is a sectional view along line III-III of Figure 2, and Figure 4 is a partial view of the syringe of Figure 1, in another position, and Figure 5 is a partial perspective view of a detail of embodiment of the invention.

Referring firstly to Figures 1, 2a, 2b and 3, there is illustrated a syringe which comprises' a syringe body 100. The body 100 comprises a main cylindrical part of revolution 102, two end wings 104 intended to maintain the body during injection, in a conventional manner, a portion of tapered tapered wall 106 situated opposite the wings 104, this tapered wall 106 extending by a cylindrical portion 108 of smaller diameter. The part 108 ends at its free end with a straight re-entrant annular rim 110.

The syringe body 100 further comprises, at the transition between the frustoconical wall 106 and the cylindrical wall 108, a small annular rib 112 extending radially inwards. The section of this rib is for example trapezoidal, with an oblique locking face turned to the left. As a variant, the rib 112 can be replaced by a recess in the interior face of the syringe body in the transition region between its part 108 and its frustoconical part 106.

Finally, two other ribs 114, 116 are provided in the syringe body, located a short distance from each other in the vicinity of the rear end, wing side 104, of the main part 102 of the body. These ribs extend circularly and radially inward of the body. Their section is for example semi-circular. In addition, the rib 116 closest to the rear end of the syringe body (right on the figures) is in the present example more salient than the other rib 114, for purposes explained below.

The syringe also comprises a piston generally designated by the reference 200. This piston comprises a piston rod 202 conventionally constituted by four perpendicular branches defining a cross-shaped section. At its free end, the rod 202 has a flat surface 204 forming a pusher.

At its opposite end, the piston has a piston head 206, the outer surface of which has a cylindrical zone, on the side of the rod 202, and a tapered tapered zone, on the side opposite to the rod. In the cylindrical zone is formed a groove 207a for a seal 250, in this case a generally 'flat seal made of elastomeric material. The frustoconical zone is intended to match the shape of the frustoconical part 106 of the syringe body 100.

On its face opposite to the rod 202, the piston head 206 comprises a frustoconical recess 206a at the bottom of which an essentially spherical cavity 209 is formed.

It can be seen in FIGS. 1, 4 and 5 that the piston rod 202 comprises, at a well-determined distance from the head 206, a frangible part defined in this case by four notches, namely two blind notches 202a extending radially inwards in two opposite branches of the rod from their outer edge, and leaving between them a solid central part, and two blind notches 202b extending radially outwards in the two other opposite branches of the rod to starting from their root region and defining a central void. In this way, a region of smaller cross section is defined in the rod, sufficiently solid for handling the piston but weakened for the purposes explained below. Advantageously, the piston rod 202, its pusher 204 and its head 206 are made in one piece by molding plastic material.

The syringe also comprises a tip-holder element, constituted by a single piece and generally indicated at 210. This element comprises a radially inner part 212 slightly frustoconical, of small diameter, intended for mounting the needle, and a part or skirt radially outer 214 whose outer face is slightly flared towards the front of the syringe (to the left in the figures). This skirt has at rest a maximum outside diameter (on the left) slightly greater than the inside diameter of the part 108 of the body, and a minimum outside diameter (on the right) substantially equal to said minimum inside diameter of the part 108. The parts 212 and 214 are joined to each other by an annular part 216.

From this annular part 216 extend radially flexible legs 218, in this case four in number and arranged in quadrants as shown in FIG. 3. Notches 219 (FIG. 3) directed axially separate said pairs in pairs. flexible lugs so as to allow, as will be seen below, their elastic movement of mutual approach towards the inside under the action of the piston head 206.

The flexibility of said legs 218 is ensured here by giving them a narrow base, indicated at 218a, near the annular part 216 of the element 210.

As FIGS. 2a and 2b clearly show, each tab 218 has, in the immediate vicinity of its narrower base 218a, a slightly frustoconical outer face 219a whose maximum diameter at rest is substantially equal to the inside diameter of the part 108 of the body of syringe, and in which is provided a hooking tooth 219c. Teeth 219c on all fours 218 extend in a coaxial circle with the rest of the syringe. Each tooth has an oblique hooking face intended to cooperate with the homologous oblique face of the rib 112 of the body, as will be seen in detail below.

Each leg 218 comprises, from the zone bordered by the outer face 219a, a re-entrant part extended by a hooking part 222 in the general shape of a quarter of a sphere, the four quarters of sphere of the four legs being essentially complementary to the cavity 222 of the piston head, but spaced apart.

The cylindrical part 212 of the bit-holder element is capable of receiving, for example by force fitting, a nozzle 230 carrying a needle 240. This nozzle is of entirely conventional design and comprises a> slightly frustoconical main part 232, the inner face of which tightly encloses the outer face of the part 212 of the bit holder 210. This part 232 ends on the side of the bit holder with a flange 234. Opposite this flange, the part 232 is extended by a closure part 236 in which the needle 240 is mounted via a tight seal.

We will now explain the assembly and use of the syringe whose structure has been described above. First, the tip-holder element 210, generally without a tip, is introduced into the syringe body 200, the skirt 214 being trapped by the re-entrant flange 110 and the homologous teeth 112, 219c locking the element 210 in position. It will be noted here that the internal surface of the part 108 of the body and its rim 110, and the external surface of the skirt 214 of the bit holder are designed, as for their profile, their diameter and their surface condition, so to ensure by elastic stress between these surfaces a seal against the liquid to be injected, thereby eliminating the need for a attached. The tip-holder element 210 acts as a shutter effect for the front end of the syringe body. In the present example, this seal is obtained by the flared shape of the skirt 214 and by the choice of diameters as indicated above.

To make the syringe operational, the plunger 200 is introduced into the syringe body 100 from the rear, and a tip 230 carrying a needle 240 is fitted onto the part 212 of the tip-holder element 210. To draw the liquid out inject into the syringe, the piston head 206 has previously been brought to the vicinity of the tip-holder element 210, taking care not to carry out the attachment between these two parts, as will be described below. . The piston is then, conventionally, pulled to suck up the liquid and pushed back for injection.

At the end of the injection, the piston is pushed forward with more firmness (arrow F1 in FIG. 2a). During this movement, the flexible tabs 218 are biased inwards by the frustoconical wall 206a of the piston head, to cause the ends 222 of the tabs 218 to engage in the spherical cavity 209 of the piston head 206 This movement of the legs 218 causes a slight offset towards the inside of their outer surface 219a, which cooperated with the rib 112, so that the bit-holder element is released on the inside, the rib 112 no longer constituting an obstacle. . At the same time, as soon as the ends 222 of the legs 218 have forcibly crossed the narrowed entry of the spherical cavity 209, a hooking engagement is made between the bit holder 210 and the piston head. The situation thus obtained is illustrated in FIG. 2b.

The piston can then be pulled backwards (arrow F2 in FIG. 2b), to drive with it the bit-holder element 210 and the nozzle 230 provided with the needle 240. The needle 240 is thus found sheltered inside the body 100.

FIG. 4 the situation in which the piston has been pulled until the piston head 206 reaches the region of the part of the body 102 in which the ribs 114, .116 are located. The seal 250 (constituted in this example by an O-ring) and the adjacent part of the piston have crossed the internal rib 114 and come into abutment against the more protruding rib 116; the ribs 114 and 116 cooperate to constitute a relatively firm obstacle to the translation of the seal 250 and of the adjacent part of the piston, and therefore of the whole piston, in one direction or the other. In this position, the frangible region of the piston rod 202 is located in the vicinity of the rear opening of the syringe body 100. By a bending force exerted manually, for example according to arrow F3 in FIG. 4, the piston rod 202 can be broken in said frangible region. The piston head then being deprived of a rod, on the one hand the syringe can no longer be used, and on the other hand it becomes much more difficult to extract from the interior of the body thereof the nozzle fitted with the needle, because a narrow tool is then necessary.

This particular arrangement can be used with the nozzle holder configuration as described above, but more generally in any type of syringe with retractable needle.

Of course, the present invention is not limited to the embodiments described and shown, but the skilled person will be able to make any variant or modification according to his spirit.

Claims

1. Syringe, of the type comprising a generally cylindrical syringe body (100), a piston (200) provided with a rod (202) and a head (206) mounted sliding in the syringe body,. a tip holder element (212) housing a fluid passage and intended to receive a standard needle tip, retaining means (112; 219c) provided between the syringe body and the tip holder element, said retaining means being able to be unlocked under the action of a movement of approximation of the piston head at the end of injection, hooking means (209, 222) provided between the piston head and the nozzle holder means for ensuring mutual attachment during said movement of approach, and then allow the traction of the tip-holder element and its needle inside the syringe body, the syringe comprising a single piece (210) constituting the tip-holder element , the retaining means and the hooking means, and this part comprising flexible arrangements (218) the sole request of which by the piston head during the bringing together movement makes it possible both to unlock the retaining means and to hooking of the hooking means, syringe characterized in that it comprises flexible sealing means (214) produced integrally with the single part, and in that the retaining means and the hooking means are constituted by a set of flexible lugs (218) capable of being intimately brought close to one another during the unlocking of the retaining means (112, 219c) and the attachment of the attachment means (209, 222).

2. Syringe according to claim 1, characterized in that the flexible tabs (218) have at their free end the form of spherical sectors (222), and in that said piston head (206) comprises, on a face turned towards said part, a generally spherical cavity capable of receiving said flexible tabs (218) by urging them inwards.

3. Syringe according to claim 2, characterized in that said flexible tabs (218) are separated by notches (219) extending in radial planes.

4. Syringe according to one of claims 2 and 3, characterized in that said flexible tabs (218) have a first part defining said spherical end sectors and a second part whose outer surface (219a) has a diameter close to the inner diameter of the syringe body (108) at the workpiece level.

5. Syringe according to claim 4, characterized in that the retaining means comprise at least one protruding arrangement (112) on the inner surface of the syringe body in the region of the part, arrangement which cooperates with an homologous protruding arrangement (219c) of said second part of each tab (218).

6. Syringe according to claim 5, characterized in that said at least provided protruding arrangement comprises a recess or an additional thickness (112) protruding towards the inside of the body, and in that said protruding arrangement (219c) of the second part of each leg has a circular profile.

7. Syringe according to one of claims 1 to 6, characterized in that the flexible sealing means consist of a substantially cylindrical flexible outer skirt (214) of said part, capable of being in sealed contact with an inner surface of said syringe body, and in that the syringe body comprises abutment means (110) of said part, the latter being immobilized axially between the retaining means (112) and the abutment means.

8. Syringe according to claim 7, characterized in that said outer skirt (214) is at rest slightly flared towards the front of the syringe and is capable of being elastically deformed by said inner surface of the syringe body to establish tight contact with it.

9. Syringe according to one of claims 1 to 8, in which the piston rod comprises several angularly spaced thin radial branches, characterized in that the piston rod (202) comprises, near the piston head, a defined frangible region by first blind notches (202a) extending radially inward from the outer edge of first branches and second blind notches (202b) extending radially outward from a root region of seconds branches.

10. A syringe according to Claim 9, characterized in that the syringe body comprises, in the vicinity of an inlet opening of ^piston thereof, means (114, 116) for stabilizing the piston head ( 206) in a position such that said frangible region is located in the close vicinity of said opening and corresponds substantially to the fully pulled piston.

11. Syringe according to claim 10, characterized in that said stabilization means comprise two ribs (114, 116) generally circular and spaced, between which is adapted to wedge a flexible seal (250) mounted on the periphery of the plunger head (206) and optionally an adjacent portion of the plunger head (206), a rib (116) closest to the rear end of the syringe being more protruding than the other rib (114) .