JPH024386A - Non-re-usable injector - Google Patents

Abstract

PURPOSE: To disable the recycle of a syringe by providing a plunge rod with an elastic block means to be pressed onto the inner wall of a syringe barrel and engaging this means with an edge so as to block the syringe barrel from moving back in reloading direction. CONSTITUTION: The syringe is loaded by moving the position of the plunger rod to a position, where a rim 15 of a member 12 touches the edge of a loop- shaped member 22, or a little lower than this position. In this case, air remaining together with liquid is exhausted by pushing down a piston rod to a position where a safety member 20 touches a clamping means 18. When performing injection, for a vein test, an operating rod 7 is pushed down to the final position after a little liquid is extracted from a patient, the full quantity of liquid in the syringe is injected and the safety member 20 is removed from the operating rod 7. After the 1st injection, the operating rod 7 is moved back and when the reload of the syringe occurs, a connecting member 8 lets the operating rod 7 follow up a piston 4 to a position, where the rim section of the block member 12 is engaged with the edge of a recessed part 19, so that the connecting member 8 can be prevented from moving up any more.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-reusable syringe, ie, a disposable syringe that can be used for only one injection.

Transmission of blood-borne diseases such as viral hepatitis or AIDS by reusing unsterilized or incompletely sterile syringes that have been contaminated with the disease virus by injecting a patient. The need for non-reusable syringes has become extremely urgent in view of the increased risk of This is important among drug addicts, where it is common to reuse syringes that have already been used by others without first sterilizing them. It is very high in poor countries of the world due to lack of sterilization methods.

Therefore, many non-reusable syringe structures have been proposed. However, this can lead to increased costs (significant complexity, lack of reliability, other difficulties such as difficulty in removing air within the syringe before injection, or low safety for all methods of syringe reuse). Due to either of these reasons, none of the conventional solutions are satisfactory.

The main objects of the invention are to provide a syringe that is relatively simple and economical, virtually eliminates the possibility of reuse, and that allows rapid and complete removal of air from the syringe prior to injection. It is to provide. The present invention is particularly directed to improvements in the disposable syringe described in US Pat. No. 4,391,272.

These and other purposes will become apparent from the description below.

The non-reusable syringe of the present invention includes a hollow syringe barrel having a first open end for attaching a hypodermic needle and a second open end opposite the first open end; a plunger assembly reciprocatable in the syringe barrel, said plunger assembly having a plunger rod and a piston member, said plunger rod having at least one peripheral portion tending to be pressed against an inner wall of said syringe barrel; said inner wall has a first recess having a sharp edge, said recess extending from said edge towards said first open end of said syringe barrel and said periphery of said resilient blocking means. The portion may be at the edge to prevent retraction of the plunger rod toward the second open end of the syringe barrel beyond the point where the peripheral portion engages the edge. and the plunger assembly is adapted to provide limited movement of the plunger rod relative to the piston member.

In one aspect of the invention, the end of the plunger rod is slidably connected to the piston member to permit said limited movement. The plunger rod preferably comprises two separate members, an actuation rod and a connecting member, one end of which is slidably connected to the actuating rod and the other end of which is slidably connected to the piston member. . The piston member preferably has an elongated cavity for accommodating the head of the plunger rod or coupling member;
The appendage has a first position in which it engages the piston member so as to be able to retract the piston member in the direction of said second open end of the syringe barrel, and a second position in which the appendage abuts a bottom wall portion of the piston member. It is provided so that it can slide between the two positions.

In a preferred embodiment, the inner wall of the syringe barrel has a second
a recess, the edge of which is disposed proximate the first recess between the first recess and the second open end of the syringe barrel. A third recess may be provided, the edges of which are similar to the second recess.
and the second open end of the syringe barrel. These recesses may be annular grooves or may be formed by steps increasing the diameter of the inner wall of the syringe barrel. The edge of each recess is circular and said resilient blocking means has at least one peripheral rim portion capable of engaging the circular edge.

Preferably, the syringe of the present invention further comprises at least one removable safety member, the safety member being such that the resilient blocking means of the plunger rod is in contact with the first and second recesses of the inner wall of the syringe barrel before use. The plunger assembly is positioned to prevent the plunger assembly from being pushed into engagement with the plunger assembly.

The invention will be better understood by reference to the following detailed description and drawings. The drawing schematically shows, by way of example, two constructional configurations of a syringe according to the invention.

The syringe shown in FIGS. 1 to 6 comprises a barrel l in the form of a hollow, generally cylindrical body having a first open end 3 adapted to receive a hypodermic needle 2. The second open end of 1 supports the upper end of an actuating rod 7 with a flat gripping member 1a and a disc-shaped gripping and actuating member 7a extending through this open end. This actuating rod 7 is part of a plunger assembly which is reciprocable within the syringe barrel and which in this example further comprises a coupling member 8 and a piston member 4. The piston member 4 has two projecting annular parts 5 and 6 which form a lower part of the piston member, thereby creating a tight partition between the lower part of the piston member 4 and the syringe barrel. while forming the piston member barrel 1
sliding along the lower portion of the cylindrical inner wall of the.

The piston member 4 has a substantially cylindrical cavity 11, which is connected to the bottom wall of the piston member forming the seat 21;
It extends longitudinally between the piston member and the opening in the upper end thereof. The coupling member 8 has a generally cylindrical body portion 9 and a generally frustoconical head 10 which is slidably inserted into the cavity 11 through the opening in the piston member. The body part 9, which is provided with Air can flow between the two.

The upper part of the coupling member 8 is formed by a frusto-conical block member 12, which is divided into a plurality of parts, for example three radially extending slots 16. Each section or slot has a rim section 15, as shown in FIG. 1, which is pressed elastically against the inner wall of the barrel 1. The parts of the barrel 1 and the plunger rod are preferably made of synthetic resin with the appropriate hardness required by their friction. Also in this example, the piston member is preferably made of rubber or an equivalent resilient material. When the part 12 of the connecting member 8 is in its free state before being incorporated into the barrel 1,
It has a shape that is slightly larger than the maximum diameter of the inner wall of the barrel 1. This means that in the position shown in FIG. 1, said part of the member 12 is easily compressed and the rim part 15 is pressed elastically against the inner wall of the barrel 1. The member 12 further has an endwardly flared cavity 13 having an internally engaging edge, the shape of which is such that the actuating rod 7 is in the condition shown in FIG.
It corresponds to the shape of the fixed neck portion 14 formed at the lower end of the. That is, this fixed neck part 14 is held in the cavity 13 in the position shown in FIG. The first wall that is in contact with the wall surrounding the empty space 11
Allow the entire plunger assembly to retract from the position shown.

The annular recesses 18 and 19 are shown as frusto-conical grooves in the inner wall of the barrel 1, each groove having a relatively sharp circular upper end. In the inner wall of the barrel 1 there is a third recess formed by increasing its inner diameter between the upper annular guide part 22 of the barrel l and the lower part of the barrel accommodating the piston member. .

The syringe of the invention further has a removable safety member 20, which surrounds its upper end and is formed integrally with the actuating rod, for example, to precisely determine the maximum insertion position of the actuating rod when inserted into the barrel 1. It is now possible to do so.

This maximum insertion position before the actual injection precisely regulates the amount of liquid to be injected, as will become clear from the description below. The member 20 may have a plurality of radially disposed blades or wings having an integral top and removably connected to the actuating rod 7, the lower end of the blade gripping the barrel. It is in contact with member 1a.

Breaking the lateral connection between each blade and the actuation rod allows the entire safety member 20 to be removed. Other removable configurations, which are initially integral with either the barrel 1 or the actuating rod 7, can be provided to suit this purpose.

The operation of the syringe according to the invention and the function of the various parts mentioned above will become clear from the following description with reference to FIGS. 2 to 6, which show the syringe in various states.

When the syringe of the invention is used for injection, it is first filled in the usual manner by pulling the liquid actuating rod 7 to be injected backwards as shown in FIG.

The syringe is generally filled by moving the plunger rod until the rim 15 of member 12 contacts the edge of annular member 22 or slightly below.

The lengths of the various parts of the syringe are chosen such that the maximum filling volume, which corresponds to the maximum retracted position of the actuating rod, is slightly larger than the actual volume to be injected. In this case, the air remaining with the liquid can be evacuated by pushing the piston rod down until the safety member 20 contacts the gripping member 18 as shown in FIG.

Comparing this state of the syringe with FIG. 1, we can see that the actuating rod 7
It will be seen that the plunger rod formed by the connecting member 8 and 8 are in the same position, but the piston member 4 has moved to a position where the seat 21 abuts the head 10 of the connecting member. This movement, as effected in this example, means that in the initial condition of the syringe, the piston member 4 is in the lowest position shown in FIG. This makes it possible to reduce the pore volume. Air removal is therefore significantly faster and easier than with conventional syringes. This is because, in conventional syringes, the piston member cannot be placed against the bottom of the barrel before filling, so that a certain amount of air is necessarily present in the initial state of the syringe.

When giving an injection, a so-called "venous test" is carried out to determine whether there is blood in the needle, i.e. to ensure that the needle is in the correct position within the patient's body.
Vein test) J is performed first. For this venous test, the actuating rod is again slightly retracted beyond the position shown in FIG. That is, the actuation rod draws a small amount of liquid from the patient while the needle is inserted. The entire amount of liquid in the syringe is then injected, the safety member 20 is removed from the actuation rod, and the actuation rod is depressed until it reaches its final position shown in FIG.

After the injection is complete, the syringe is discarded.

FIG. 5 shows what happens after the first injection when an attempt is made to refill the syringe by retracting the actuation rod. The connecting member 8 has a rim portion of the member 12 in a recess 19.
The actuating rod 7 follows the piston until it engages the edge of the piston, thereby preventing further upward movement of the connecting member.

In this embodiment, the recess 13 of the elastic member 12 is such that the elastic rim portion is in the recess 13 when in the position shown in FIG.
9 and thus a further retraction is attempted, another safety measure is provided by the fact that the conical neck member of the actuating rod 7 disengages from the coupling member 8. The position of the edge of the recess 19 is preferably chosen to be close to the actual end of the piston member 4, so that the piston member is in the position of FIG. pole (which results in only a slight rise) until it touches the head; this means that a fresh filling of the syringe is not possible by retracting the actuating rod, and that the piston member cannot be refilled through the opening of the barrel on the needle side. Any attempt to influence will not be successful,
It means that.

FIG. 6 shows another attempt to reuse the syringe, i.e. without injecting the entire amount of liquid, with the syringe being placed in a position before reaching its final position leading to the piston member being blocked. It shows. When retracting the actuating rod 7 from a position where the connecting member 8 is not yet engaged with the recess 19, the resilient blocking member 12 engages the edge of the second recess 18 located slightly above the edge of the recess 19. engage. In this position, when a retraction force is applied to the actuating rod 7, it separates again from the coupling member 8 in the same way as in FIG. It is therefore not possible to move the piston member 4 upwards by means of the actuating rod 7, and it is not possible to fill the syringe with further liquid by suction. That is, the syringe of the present invention is completely non-reusable.

Another embodiment of the invention is shown in FIG. FIG. 7 corresponds to FIG. 1 and shows the syringe in its initial state.

In this example, the actuating part and the connecting part of the plunger rod are made integral with each other and cannot be separated. The plunger rod has an upper actuation part 37, a block part 39, a bar part 38 and a head 40. 8th
In the longitudinal section of the figure, the block part 39 comprises, for example, four segments separated by small radial slots, forming an elastic block part that cooperates with a recess provided in the inner wall of the barrel 31 in this example. There is. barrel 31
The inner wall of the recess 4 is formed as a step where the inner diameter of the barrel increases towards the bottom of the barrel containing the piston member 34.
1 and 42. The elastic block portion 39
It cooperates with the recesses 41 and 42 in the same way as in the illustrated example, so the operation of this syringe is substantially the same.

The main difference, as already mentioned, is that the actuating part and the connecting part are inseparable from each other, so that the other safety mentioned with respect to FIGS. 5 and 6 is not obtained in this example. .

The stepped shape of the recesses 41 and 42 facilitates the manufacture of the syringe by molding and reduces its price.Other structural differences allow the necessary tightness to be attached to the body part. By attaching a sealing means such as an O-ring to the piston member, the body portion of the piston member can be constructed from a plastic other than rubber.

The various structural features described above in connection with the example of FIG.
Each can be applied singly or separately to the embodiment of FIG. The basic functional advantages of the invention, namely virtually complete safety for reuse and high reliability of operation, are retained in any combination within the scope of the claims.

[Brief explanation of the drawing]

1 is a longitudinal cross-sectional view of a syringe according to a first embodiment of the invention in its initial state before use, i.e. ready to be stored and transported; FIG. FIG. 3 is a cross-sectional view similar to FIG. 1 of the syringe of FIG. 1 filled with liquid, and FIG. 3 is a cross-sectional view similar to FIG. 1 of the syringe of FIG. 1 ready for injection; FIG. 4 is a cross-sectional view similar to FIG. 1 of the syringe of FIG. 1 after the injection has been completely performed, and FIG. 5 shows that the piston member is in the barrel after injection. 6 is a cross-sectional view similar to that of FIG. 1 of the syringe of FIG. 1 after an attempt has been made to withdraw it from one end of the position; FIG. 7 is a cross-sectional view similar to FIG. 1 of the syringe of FIG. 1 after an attempt has been made to retract it from a position prior to the end position of the piston member; FIG. 7 shows a second embodiment of the invention; FIG. 8 is a longitudinal cross-sectional view showing the example syringe in its initial state before use; FIG. 8 is a cross-sectional view taken along the line ■-■ of FIG. 7 showing the syringe of FIG. 7; 1... Barrel, 2... Needle, 4... Piston member,
7... Operating rod, 8... Connecting member, 9... Main body portion, 10... Head, 12... Block member, 19
... recess, 20... safety member, 37... upper operating part, 39... block part, 38... rod-shaped part,
40...Head. Patent Applicant Jacques Berrière FIG, 4 FIG, / FIG, 2 FIG, 3

Claims (15)

[Claims] (1) a hollow syringe barrel having a first open end for attaching a hypodermic needle and a second open end opposite the first open end; and a plunger assembly reciprocable within the syringe barrel. , the plunger assembly having a plunger rod and a piston member, the plunger rod having resilient blocking means having at least one peripheral portion tending to be pressed against an inner wall of the syringe barrel, and the inner wall having a a first recess having a sharp edge, said recess extending from said edge towards said first open end of said syringe barrel, said peripheral portion of said resilient blocking means having said peripheral portion; the plunger rod is adapted to engage the edge so as to prevent the plunger rod from retracting in the direction of the second open end of the syringe barrel beyond the position where it engages the edge; and wherein the plunger assembly is adapted to provide limited movement of the plunger rod relative to the piston member. (2) the plunger rod has a first end extending through the second open end of the syringe barrel and a portion of the piston portion configured to permit limited movement of the plunger rod relative to the piston member; 2. The syringe of claim 1, wherein the syringe has a second end slidably connected thereto. (3) the plunger rod comprises two separate members, an actuation rod and a connecting member, each having a first and a second end, the first end of the actuation rod being the first end of the syringe barrel; 2, the second end of the actuating rod having means for removably securing the second portion of the actuating rod to the first end of the connecting member. wherein the first end of the connecting member comprises the resilient blocking means and the second portion of the connecting member is slidably connected to the piston member, thereby tightening the plunger rod relative to the piston member. 2. The syringe of claim 1, wherein said limited movement of is allowed. (4) The piston member has an opening in the piston member through which the second end of the plunger rod passes, and a bottom wall portion of the piston member that faces the first open end of the syringe barrel. an elongate cavity disposed therebetween, the second end of the plunger rod having a head slidably disposed within the elongate cavity, the position of the head being such that this a first position in which the head engages the member to permit retraction toward the second open end of the syringe barrel; and a second position in which the head abuts the bottom wall portion of the piston member. The syringe according to claim 2, wherein the syringe is selected between. (5) The piston member has an opening in the piston member through which the second end of the connecting member passes, and a bottom wall portion of the piston member that faces the first open end of the syringe barrel. an elongate cavity disposed therebetween, the second end of the connecting member having a head slidably disposed within the elongate cavity, the position of the head being such that the a first position in which the head engages a piston member to permit retraction toward the second open end of the syringe barrel; and a second position in which the head abuts the bottom wall portion of the piston member. The syringe according to claim 3, wherein the syringe is selected between. (6) the inner wall of the syringe barrel has a sharp edge disposed proximate the first recess between the first recess and the second open end of the syringe barrel; Second
The syringe according to any one of claims 1 to 5, having a recess. 7. The syringe barrel has a third recess with a sharpened end disposed between the second recess and the second open end of the syringe barrel. Syringe. (8) said first recess is an annular groove provided in said inner wall of said syringe barrel, and its edge is circular, and said resilient blocking means is capable of engaging said circular edge; The syringe of claim 1, having at least one peripheral rim portion. (9) said first and second recesses are annular grooves provided in said inner wall of said syringe barrel, and their edges are circular, and said resilient blocking means engages said circular edges; 7. The syringe of claim 6, having at least one peripheral rim portion capable of (10) at least two of the first, second and third recesses are annular grooves provided in the inner wall of the syringe barrel, and the edges of the at least two recesses are circular; 8. The syringe of claim 7, wherein the resilient block member has at least one peripheral rim portion engageable with the circular edge. (11) the first recess is formed by a step of increasing diameter on the inner wall of the syringe barrel, the edge of the first recess is circular, and the elastic block member is at least one capable of engaging the circular edge
A syringe according to claim 1 having two peripheral rim portions. (12) the first and second recesses are formed by steps of increasing diameter in the inner wall of the syringe barrel;
The syringe of claim 1, wherein the edges of the first and second recesses are circular and the resilient block member has at least one peripheral rim portion engageable with the circular edges. . (13) at least two of the first, second and third recesses are formed by steps of increasing diameter on the inner wall of the syringe barrel, and the at least two edges are circular; 8. The syringe of claim 7, wherein said resilient block member has at least one peripheral rim portion engageable with said circular edge. (14) the resilient blocking means of the plunger rod prevents the plunger assembly from being pushed into a position where it engages the edge of the first recess in the inner wall of the syringe barrel prior to use; A syringe according to any one of claims 1 to 5, 8 or 11, comprising at least one removable safety member arranged to do so. (15) the resilient blocking means of the plunger rod prevents the plunger assembly from being pushed into a position where it engages the edge of the first recess in the inner wall of the syringe barrel prior to use; A syringe according to any one of claims 6, 7, 9, 10, 12 or 13, comprising at least one removable safety member arranged to do so.