BE1007043A3 - SINGLE SELF-DESTRUCTIVE SYRINGE. - Google Patents

Abstract

The syringe comprises a device (4) making it possible to secure the push rod (3) with the reservoir (1) by the perforation of the latter (1). The device (4) is integrated into the push rod (3) and accompanies it during transfers of the filling as well as during a certain part during injection. When lowering, the device (4) stops interrupting its joint movement with the push rod (3) creating a differential stroke used for the extension of the device (4) carrying a point (6) causing the perforation of the reservoir ( 1) as well as the cutting of the tank during an attempt to refill. A case (8) allows the extraction of the needle in order to eliminate the risk of accidents during handling. By separating from the syringe, the case causes deterioration of the syringe (1).

Description

SINGLE SELF-DESTRUCTIVE SYRINGE

The present invention relates to medical instruments intended for injecting liquids into the tissues and relates to a syringe.

Known syringes comprise a pump body provided on the one hand with a finger rest guard and on the other hand with a needle holder nozzle, and a movable assembly composed of a push rod and a sealing piston integral with said push rod. By this design, the filling and injection actions can be repeated multiple times until wear. This results in risks of contamination by HIV virus and others due to re-use. The free sale and free distribution of syringes are bringing no result to the resurgence of the scourges of drug addiction and AIDS.

Syringes operating in a similar fashion to known syringes but which can only be used once have been described in Belgian patent applications Nos. 09200486 and 09200934.

Studies have already been done to offer disposable syringes. Most of these projects most often call for the implementation of too many parts, in particular a new design of pump body leading to a change in the production dies. This results in an investment as well as too high a cost affecting the unit price.

From the technical point of view, systems are also used which use the stop at the end of the piston stroke for securing or detaching the device, breaking a membrane, cutting the reservoir during the first injection, etc. These systems have many disadvantages of use compared to known syringes: they can be rendered ineffective by the user who stops the stroke of the piston before the latter reaches the bottom of the reservoir, and they do not allow '' perform a control aspiration during specific injections such as the IV.

All of these provisions are intended to prevent re-use of the syringe, but do not eliminate the dangers posed by the needle when it is left on the syringe, or when it is extracted from the syringe.

It has also been proposed to provide for automatic withdrawal of the needle using a spring, the needle being integrated into the pump body. This solution makes it impossible to select the desired needle lengths.

The invention therefore aims to provide a syringe of the above type, but not having these drawbacks.

According to the invention, the syringe comprises means adaptable to the pump bodies existing on the market without modification of the manufacturing dies thereof. A first means makes it possible to render a syringe unusable by the deterioration of the pump body. This means secures the push rod with the body during injection using a single piece incorporated in the push rod. Said part has a cutting tip. The respective profiles of the groove of the push rod and of said part, during a relative displacement, cause the separation of this part, the point of the latter coming to perforate the reservoir at a point and thus initiating the cutting of the tank when trying to refill. As the activation of this device takes place in a terminal injection phase, it cannot be located by the operator. This terminal route represents approximately 1/4 to 1/5 of the capacity of the syringe.

The first means already being sufficient to solve the problem of non-reuse can be supplemented by a second means making it possible to eliminate the risk of accident by pricking an infected needle. This second means consists of a case covering the needle and extracting it from the pump body. This case has a conical internal part enclosing a ring interposed between the needle and the pump body. This ring retains the case by pointed elements coming into contact with the needle holder nozzle or which can also be in contact with the pump body.

When the case is dragged, the diameter of the ring decreases, and the pointed elements deteriorate the nozzle or the reservoir when the case is separated from the syringe. The small hooked tabs located on the front face of the ring also follow the reduction of the ring and come to grip and hold the collar of the needle. The needle thus held cannot come out of the case and therefore no longer presents a danger during handling, storage, etc. The case thus absorbs needles having the most common lengths. In the case of an unusually long needle, there is always the possibility of replacing the protective cap.

The advantages obtained with a syringe according to the invention can be summarized as follows: - The syringe is rendered unusable after a first use.

- After use, the needle is removed without any contact of the user's hand with the needle.

- The handling is simple and identical to the handling of common syringes.

- The initial perforation of the reservoir during the injection facilitates its subsequent cutting by a greater effort after the injection, resulting in more comfort for the patient.

A syringe according to the invention constitutes indisputable progress for the safety of the user, medical personnel or the like, contamination by HIV virus by contact with used needles being reduced to a minimum.

From the technical point of view, the simple design of this syringe makes the invention compatible with automatic manufacture.

The miniaturization of all the internal parts of the syringe also makes the invention applicable to very small syringes, for example 1 ml syringes.

The invention is now described in more detail with the aid of the accompanying drawings.

FIG. 1 is a longitudinal section of an exemplary embodiment of a syringe according to the invention, the device being in position before aspiration.

Figure IA is a cross section through the syringe.

Figure 2 shows the syringe of Figure 1 in the maximum filling position.

Figure 3 shows the syringe of Figure 1 in position at the end of injection, with a case fitted to the syringe before extraction of the needle.

Figure 4 is a section through the case, with a variant ring.

Figure 5 is a sectional view showing the case shown in Figure 3, after separation from the syringe.

Figure 6 is a section along line VI-VI of Figure 5.

FIG. 7 is an exploded view of the push rod shown in FIGS. 1 and 3.

Figure 8 is a section through a syringe comprising an alternative embodiment of the securing device comprising two stop hooks, the syringe being in the filling start position.

Figure 9 shows the syringe of Figure 8 at the time of maximum filling.

Figure 10 shows the syringe of Figure 8 at the end of injection.

Figure 11 shows in section a syringe comprising another alternative embodiment of the device according to the invention.

Figure 12 shows the syringe of Figure 11 in the maximum filling position.

Figure 13 shows the syringe of Figure 11 in position at the end of injection.

FIG. 14 is an exploded view of the push rod shown in FIGS. 11 to 13.

As seen in Figures 1 and 2, the pump body or reservoir 1 contains a piston 2, of known type, and a push rod 3 having a cross section. A diametral wing is provided with a longitudinal cavity having two sectors joined by a stiffening rib and serving to support a device 4 consisting of a blade whose end located on the side of the piston 2 is of flared shape. The blade 4 carries a pointed element 6 which can be cutting in the direction of traction on the push rod 3. The point 6 is arranged opposite the internal wall of the reservoir 1. The upper end of the device 4 comprises a more thick and forms a step 41. Diametrically opposite this step is located a slightly compressed strip 42 which brings out the thicker part. The step 41 which exceeds the inside diameter of the reservoir 1, limits and stops the descent of the blade 4 during an injection. On the side of the push rod 3, the flared end of the blade 4 rests on an inclined flank 31 forming a wedge whose tip is oriented towards the piston 2. In this way, during a relative displacement of the rod 3 relative to the blade 4 during an injection, it causes the blade to extend into the pump body 1.

It is observed that the inclined side has a small step 32 ending in a part parallel to the general axis. On the side of the push-button, the rod 3 has a sector 3 "used to hold the blade 4 when it is activated during an injection (see FIG. 3). On the other hand, on the side of the piston 2 the rod 3 rests on a washer 21 placed on a shoulder of the head of the pusher 3. The diameter of this shoulder is substantially larger than the head of the tenon of the piston 2.

It should be noted that the assembly of the parts of the rod 3 is carried out as follows: placement of the stop ring 5, placement of the washer 21 then of the piston 2, and finally placement of the blade 4. Like the blade 4 is held by the stop ring 5, the introduction of the rod-piston assembly as well as the stop ring 5 is done in a single operation, the stop ring being placed level by the push of the pins 7 located on the ribs of the push rod 3. The ring 5 cannot come out because it is provided with small asperities fitting into the body of the tank 1.

Figure 2 shows the blade 4 in its housing. Note the stop ring 5 which allows the push rod 3 to pass through a cruciform recess. The ears 51 of the ring 5 come into contact with the washer 21 when the push rod 3 tries to get out of the pump body 1.

It is interesting to note that it is impossible to falsify the syringe before use. Indeed, during an attempt to exit the push rod 3, this would cause the separation of the piston 2 from the head as a result of the meeting of the washer 21 and the ring 5. In addition, this washer would hamper also a re-fitting of the piston 2 on the head of the post. In addition, an attempt to exit the blade 4 would cause premature expansion of the blade and this would also result in blockage of the push rod 3.

When filling the syringe, a pull on the push rod 3 brings out the upper end of the blade 4 comprising the step 41. The output of the blade is made possible by the extension of the strip 42. The blade 4 accompanies in this position the push rod 3 during the various transfers necessary for specific injections such as, for example, the intravenous. The use of the syringe is similar to that of known syringes. The device 4 only comes into action in a terminal area defined by the distance D. The area D is defined by the length of the spacer flank 31 and its angle of attack. Depending on the syringes, zone D represents approximately 1/4 to 1/5 of the maximum capacity of the syringe.

During the descent of the push rod 3 for injection, the step 41 abuts at the entrance of the pump body 1 and causes the blade to stop 4. As soon as the blade 4 stops, there remains still the zone D to be traversed by the piston 2 and the push rod 3. This zone D is used for the sliding of the flared part of the blade 4 under the effect of the spacer flank 31. The point 6 then causes the perforation of the tank 1 at a fixed point. It is therefore impossible to refill the syringe again because traction on the push rod 3 would either lead to deterioration or to cut off the reservoir 1 if the tip 6 is sharp.

Figure 3 shows the syringe at the end of injection, the push rod 3 being secured to the pump body 1 by the piercing thereof. The small step 32 located behind the spacer flank 31 secures the blade 4 during a pull on the push rod 3.

Also shown in FIG. 3 is a case 8. This case has a cylindrical internal part 81 and a conical part 82 ending in a step 83 which leaves an opening practically equal to the external diameter of the reservoir 1 of the syringe. The case 8 is held by a ring 9 inserted in the opening and the needle holder nozzle 11. The ring 9 is split transversely to form three sectors joined together by molding or using a ring 10. The gap sectors is useful to form a reduction in diameter of said ring against the conical part 81 of the case 8. In the bore marrying the nozzle 11 are provided pointed or cutting elements 91 which hold this ring 9 thus than the case 8. The front face is furnished with at least three hooked tabs 92 forming an inside diameter substantially smaller than the outside diameter of the collar of the needle 0 but which does not hinder normal placement of the needle. this.

Figure 4 is a longitudinal section in the case 8 with an alternative embodiment for the ring 9. Here the bore in contact with the nozzle is smooth while claws 91 contact the reservoir 1 and combine with the parts 92 from inserting the collar 0 of the needle during its extraction. The elements 9 and 91 can be housed in a longitudinal groove that would include the case 8. The non-boss parts formed by the groove would then be closer to the pump body, hence a better view of the content.

Figure 5 shows the case 8 after its separation from the body 1 of the syringe. When pulling on the case 8, the conical internal part 81 causes a reduction in diameter of the ring 9 and the elements 91 which it contains are inserted into the needle-holder nozzle 11. The internal step 82 comes then take the ring 9 out of the nozzle 11. The separation causes damage to the nozzle 11 or the reservoir 1 (visible in FIG. 4) by the elements 91. It is noted that the needle cannot come out of the case 8, because it is held by the lugs 92 of the ring 9, the latter being wedged in the case 8. As shown in the cross-sectional view of FIG. 6, the ring 9 has three sectors joined by the ring 10 as well as by the arrangement of the elements which contacts the needle-holder nozzle and by the tabs 92 which enclose the collar of the needle 0.

Figure 7 is an exploded view of the push rod. In dotted lines are shown the positions of the stop ring 5 and the blade 4 in its housing. The push rod is assembled in the following order: Placement of the blade 4 in the groove of the push rod 3;

Placement of the stop ring 5 holding the blade 4 back;

Placement of the washer 21 for supporting and guiding the rod 3;

Placement of the piston 3, the assembly 2, 21, 3, 41, 5 being introduced into the body of the syringe in one operation without the aid of a depth gauge.

FIG. 8 shows the syringe with a blade 4 with double stop steps 4 '. The upper ends are in contact with the central rib 33 near the push button 3 in the filling start position. The rib at the bottom of the groove of the push rod 3 is interrupted to allow a step 41 of the blade 4 to pass.

Figure 9 shows the syringe in the filling state, with the piston 2 and a support washer 21 in contact with the stop ring 5. We observe the impossibility of removing the blade 4 from its housing because a pull on this blade 4 would cause the wedge blocking of the wedge carrying the tip 6. We also see that a first pull on the push rod 3 brings out the steps 41 from the periphery of the push rod 3 and the opening of the stop ring 5.

FIG. 10 shows the syringe at the end of an injection during the descent of the push rod 3. The steps 41 stop the blade 4. When the blade 4 stops, the piston 2 carried by the push rod 3 continues the remaining distance D '. The flank 31 causes the tip of the blade 4 carrying the tip 6 to extend.

FIG. 11 shows a syringe comprising a securing device according to the invention using a blade 4 not exceeding the periphery of the push rod 3, which prevents the blade from being extracted from the push rod 3. The ring 5 has internally, a lug 51 on which the blade 4 slides during filling of the syringe. Figure 12 shows the syringe in the full fill position. During an injection, the blade 4 slides on the lug 51 until its step 41 abuts against the lug 51 (FIG. 13). The tip 6 at the base of the blade 4 is then engaged in the wall of the reservoir 1. The assembly of the piston rod is illustrated by the exploded view of FIG. 14. The thickness of the lug 51 is adapted to the width of the groove of the push rod 3 and the diameter of the head of the piston post so that the ring 5 can be easily threaded onto the push rod. This embodiment has all the advantages of the previous embodiments and further guarantees that the blade cannot be extracted from the push rod.

Claims (13)

1. Syringe for medical use comprising a pump body forming a reservoir and a movable assembly composed of a push rod and a piston secured to the push rod, characterized in that it comprises a fastening device (4) mounted in the push rod (3) and arranged to perforate the pump body (1) at the end of use. 2. Syringe according to claim 1, characterized in that the securing device consists of a blade (4) carried by the push rod (3) and sliding in a groove that comprises said push rod (3), the blade ( 4) carrying a tip (6) arranged to cooperate with the internal wall of the pump body. 3. Syringe according to claim 2, characterized in that the bottom of the aforementioned groove comprises an inclined relief (31) oriented towards the piston (2), said relief (31) having a step (32) behind the inclined part and ending with a bearing parallel to the longitudinal axis, the bottom of the groove forming a stiffening rib serving as support for the blade (4), the step (32) securing the blade during evacuation so that, when an attempt is made to refill, the reservoir is cut out, made easier by the initial perforation. 4. Syringe according to claim 2 or 3, characterized in that the blade (4) has a part widening towards the piston (2) to cooperate with the inclined relief (31), the opposite edge of the blade being provided with 'a tip (6) cooperating with the internal wall of the reservoir (1), the upper end of the blade com carrying a wider part forming at least one step (41) and provided with an elastic strip (42) ensuring, from the first pull on the pusher (3), the output of the blade (4) so that the step (41) exceeds the outside diameter of a ring (5) and that, during the descent of the push rod (3) for injection, said step (41) causes the blade (4) to stop and interrupts its descent together with the push rod (3) while the piston (2) with the pusher (3) travels another final stroke which is used for the extension of the flared part of the blade (4) at a fixed point. 5. Syringe according to any one of claims 1 to 4, characterized in that the piston (2) is placed on a washer (21) serving as its seat and guides the push rod (3) in the pump body (1) whose internal diameter is equal to the external diameter of the washer (21), said washer (21) being placed on a shoulder present at the end of the push rod (3), the diameter of said shoulder being substantially larger than the diameter of the head holding the piston (2), so that, when trying to exit the push rod (3) out of the pump body (1), the washer (21) comes to abut against the ring d 'stop (5) and thus causes the piston (2) to come out of the tenon during greater traction on the push rod. 6. Syringe according to any one of claims 1 to 5, characterized in that the orifice of the head of the pump body (1) is provided with a stop ring (5) preventing the exit of the assembly movable outside the pump body (1) while guiding the movable assembly during its sliding. 7. Syringe according to claim 6, characterized in that the stop ring (5) holds the blade (4) in the groove of the push rod (3) so that the movable assembly is positioned automatically at the stop ring using lugs (7) provided on the ribs of the push rod (3). 8. Syringe according to any one of claims 1 to 7, characterized in that it comprises a holster (8) for engaging the syringe and allowing the needle (0) to be extracted so that when said holster containing the needle separates from the syringe, it deteriorates the needle holder nozzle or the reservoir. 9. Syringe according to claim 8, characterized in that the case comprises, after opening, a cylindrical internal part substantially larger than the diameter of the pump body (1) and sliding on a ring (9), the cylindrical part (81) ending in a conical section (82) ending in a step (83) leaving an equal opening and joining the pump body (1). 10. Syringe according to claim 9, characterized in that the ring (9) is placed between the opening of the case (8) and the needle holder nozzle (11), this ring (9) holding the case ( 8) on the syringe. 11. Syringe according to claim 9 or 10, characterized in that the ring (9) consists of several sectors joined by a ring (10) or by molding, so as to allow the diameter of the ring to be varied. 12. Syringe according to claim 9 or 10, characterized in that the ring (9) is provided with cutting elements on its wall coming into contact with the nozzle (11), so that, under the thrust of the wall conical (82) of the case (8), said cutting elements are inserted into the nozzle (11) or the reservoir (1) and cause their damage when the said case is separated from the syringe. 13. Syringe according to any one of claims 9 to 11, characterized in that the front face of the ring (9) is provided with at least three hooked parts (92) holding the collar of the needle (0) during sliding the case so that the needle (0) cannot come out of the case (8).