CN1029199C - single use hypodermic syringe - Google Patents

Abstract

The invention discloses a disposable hypodermic syringe. Wherein, the sealing front surface (31) of the sleeve joint pipe (3) is provided with an easy broken wall (34), the back surface (32) of the sleeve joint pipe is provided with at least another opening (35) besides the hole (33), the opening is positioned outside the contact range of the transmission needle (4) and the sleeve joint pipe (3) and is communicated with the back chamber (12) of the cylindrical needle cylinder (1), the transmission needle (4) is provided with a transmission needle head (44) on a positioning pin (43) for placing the sleeve joint pipe, and the needle head punctures the easy broken wall (34) under the action of the plug injection thrust.

Description

The present invention relates to a single-use hypodermic syringe comprising a cylindrical barrel containing a plunger with a cylindrical hollow socket having a seal capable of sealing with the cylindrical barrel. Peripheral wall, a closed front, and a rear with a hole for seating the socket over the dowel of the plunger drive needle.

Although this extremely common syringe with countless manufacturing and usage volumes per year is usually referred to as a disposable syringe, a syringe of this structure may not become obsolete after being used once.

This known syringe, since it is mainly made of inexpensive synthetic materials, can only be regarded as a disposable syringe, and not as a single-use syringe, and certainly not as a single-use syringe. The type of syringe in which the needle is changed rather than thrown away.

However, since blood-borne diseases are highly contagious, there is a need for a syringe which is structurally unusable.

A prior art disposable syringe (US-A-4687467) has a pointed extension at the rear of the injection needle which reaches a projection in the cylindrical barrel. When the injection plug reaches the end of the stroke, that is, when it reaches the position to push out the liquid, its sleeve is pierced by the tip of the injection needle. Due to the hollow structure of the transmission needle, the two cavities of the cylinder are communicated, which completely prohibits re-action.

However, the syringe can still be used if the first user does not completely empty the barrel (intentionally or accidentally), that is, draws in more fluid than is intended to be injected. use again.

In addition, the shape of the rear part of the injection needle of this syringe, the socket tube, and especially the end of the injection plug is complicated, that is, the driving needle and its positioning pin all need special manufacturing methods.

There is also a disposable syringe of a completely different shape (EP AI 0291109). The structure of this syringe is completely different from that of conventional syringes, because it replaces the sealed sleeve at the end of the plunger with a disc equipped with a sleeve, and the plunger rod can slide in the sleeve, so that when pushing the plunger rod When (injection phase) break the center of the disc. Its tightness is ensured by the injection needle sealing the ruptured hole in the disc. When the injection plug is pulled back, the injection needle is pulled out from the hole in the disk, and the two chambers of the injection plug communicate.

However, since there is a flange on the plunger rod which presses onto a flange in the socket behind the plunger disc, it is not possible to effectively communicate the two chambers so that the syringe can again be refilled. Fluid-filled, in other words, syringes are not single-use at all.

In addition, it is impossible to economically and conveniently process such a filling disc that is sealed for liquid suction and liquid discharge in actual manufacturing.

The object of the present invention is to overcome the aforementioned disadvantages and to propose an improved syringe according to the usual ones, which is truly single-use and which is at the same time as easy and economical to manufacture as the known syringes.

To this end, the invention relates to a syringe as described in the opening part, characterized in that:

- the closed front of the socket includes a breakable wall;

- at the rear of the socket, in addition to a hole, there is at least one other opening, outside the range of contact between the drive needle and the socket, which allows the interior of the socket to communicate with the rear chamber of the cylindrical barrel;

- the driving needle (4) has a driving needle on the positioning pin on which the socket is placed, The driven needle is used to pierce the breakable wall under the thrust of the plunger.

When the user applies a pushing force to the plunger rod, the driving needle breaks through the wall in front of the socket, so the syringe of the present invention is really a disposable syringe. Even if there are malicious users to use any means, this result is also inevitable, no matter the user wants to use the syringe again or wants to use the discarded syringe again.

Other features of the present invention are:

- the drive pin has a rod connecting the dowel pin to the plug end plate;

- The length of the shaft of the driving needle is actually greater than the thickness of the socket, so that the socket moves between the following two positions: in the first position, the back of the socket is next to the transverse surface of the positioning pin of the driving needle, at this time On the injection plug, the pulling force of the suction is exerted; while in the second position, the back is next to the end plate, and the injection liquid is pushed out of the syringe at this time;

- When pushing force is applied to the fluid in the syringe through the injection plug, the transmission needle pierces the breakable wall, and the sealing of the sleeve is guaranteed by the end plate sealing the opening, and when the injection plug is pulled, it is in the retracted position , the driving needle is separated from the breakable wall by a certain distance;

- the syringe has a locking device that prevents retraction of the plunger outside the cylindrical barrel;

- There is an annular groove on the injection plug that can break the injection plug;

- cylindrical barrels are made of two parts assembled to each other;

- The syringe also has a stop that completely prevents the movement of the plunger as long as the user does not follow the working procedure.

The back of the socket is provided with openings to be closed by the transverse plate of the injection plug.

According to additional characteristics:

- the rod of the drive pin is actually longer than the thickness of the socket so that the socket moves between two positions: the first position where the face of the socket is next to the end plate and movement between a second position in which the face of the sleeve abuts the transverse face of the conical locating pin constituting the drive pin;

- In the first position, the needle pierces the breakable wall, and the sealing of the sleeve is completed by the end plate sealing the opening. When the driving needle is in the second position and the breakable wall has a certain distance, at this time , the socket pipe ensures that the two chambers of the cylindrical syringe communicate;

- The locking device prevents the retraction of the plunger of the cylindrical syringe;

- The injection plug is tapered by an annular groove to make it easy to break;

- Cylindrical barrels are assembled in two parts;

- The stop device completely stops the movement of the plunger as long as the working process is not continued.

The following description in conjunction with the accompanying drawings will further comprehend the present invention. in:

- Figure 1 is a front view of the present invention;

- Figure 2 is an enlarged view of a part of Figure 1;

- Figure 3 is the rear view of the socket;

- Figure 4 is a partial view of the opening of the rear end of the cylindrical syringe;

- Figure 5 is a view along the arrow V in Figure 4;

- Figure 6 is an assembly diagram of the syringe of the present invention;

- Fig. 7 is another embodiment of the syringe of the present invention;

- Figure 8 is a view along the arrow VIII of Figure 7;

- Figure 9 is a cross-sectional view of a syringe according to a second different embodiment of the invention.

The hypodermic syringe shown in Fig. 1 has a cylindrical barrel 1, the open end of this barrel is bordered by a flange 19; the other end has a conical base 13, and the terminal end of this base has a short open tube of small size. 14. The open short tube is used to install the injection needle 5.

The cylindrical barrel 1 accommodates an axially movable plunger 2; the plunger has a flat surface 21, The user exerts force on the outer end of the cylindrical barrel 1 , and the end of the plug located inside the cylindrical barrel 1 has a driving needle 4 on which a hollow sleeve 3 is fitted.

The outer periphery of the socket tube 3 made of elastic material is close to the inner wall of the cylindrical syringe 1 and seals the syringe into two chambers 11 and 12 .

According to Fig. 2, the driving needle 4 of injection plug 2 comprises in turn:

- horizontal panels 22;

- a rod 41 extending from the plate 22 along the longitudinal axis of the syringe to the front end of the syringe;

- a generally conical or conical positioning pin 43 at the end of the rod 41, having a transverse face 42 on the rear side and a driving needle 44 on the front side.

With deformable material, for example the socket pipe 3 that rubber material is made is the integral structure of hollow cylinder, and its front 31 is closed, and the back 32 has axial opening 33, and the diameter of this opening is approximately equal to the diameter of transmission needle bar 41 .

The closed front face 31 of the socket tube 3 is of unequal thickness, with the central part 34 being thinner and thus easily torn or punctured. The frangible middle portion 34 is either molded as a single piece from a sheet, or as a socket with an opening at the front of the middle portion 34, and a thin, frangible disc The shape plate is fixed to this opening by ultrasonic welding or by any other known method.

The face 32 has further openings 35 , here three in number.

As shown in FIG. 3, these openings 35 are distributed along the circumference, and their centers are on the average circumference between the disc covered by the plate 22 and the disc covered by the transverse surface 42 of the positioning pin 43 .

The thickness of the rear wall 36 of the socket 3 is significantly smaller than the length of the rod 41 in order to allow axial movement of the socket along the rod 41 between the plate 22 and the face 42 . The plunger is free to move between the two ends of the rod 41 as long as the socket is positioned in the syringe.

In order to make the face 31 of the socket tube 3 close to the bottom 13 of the syringe, the injection plug 2 is inserted into the Barrels are made into syringes and sold as such.

When using for the first time, pull the injection plug 2 along the direction in which the injection plug comes out of the syringe 1, so as to suck the injection solution. During this time, the face 32 of the socket 3 bears against the face 42 of the drive needle 4 .

When pushing the plunger towards the bottom 13 of the cylindrical barrel, first the plunger 2 is moved relative to the socket 3 until the plate 22 of the plunger 2 abuts against the face 32 of the socket.

When the injector plug and the transmission needle move relative to the socket pipe 3, the transmission needle head 44, which is separated from the surface by a small distance, will pierce the breakable part 34 on the surface 31 of the socket pipe 3. In addition, when the plunger is pushed, due to the resistance of the liquid against the face 31, the face 31 is deformed to ensure that the driving needle penetrates the face.

When the plunger 2 moves towards the bottom of the cylindrical barrel, the plate 22 abuts against the face 32 of the sleeve and seals the opening 35, so that the syringe works as a syringe of known shape and the cavity is closed by the injection needle 5. The fluid contained in chamber 11 is drained.

So far, from the user's point of view, the function of this syringe is at least the same as that of known forms of syringes, except that the hub is not pierced by the needle, otherwise the user can see that the present invention can very advantageously enable the driving needle 44 to pierce the socket. Broken socket 3.

In order to ensure a seal between the plate 22 and the face 32, the opening must be positively closed. If necessary, a flange protruding from the face 32 and facing the plate 22 can be provided, the diameter of which should be large enough to cover the opening 35 .

Since the sleeve 3 connects the two chambers 11 and 12, the syringe cannot be refilled with liquid, so it cannot be reused.

In order to prevent the user from taking out the injection plug 2, liquid is filled into the cylindrical syringe 1 from the open end of the syringe 1, and a locking device is installed in the syringe at the open end.

As shown in Fig. 4 and Fig. 5, these locking devices can be tongue mouth 15 shapes, make this tongue mouth by opening some breaches on the wall of cylindrical syringe 1, these tongue mouths are moved toward the axis of syringe The walls are separate and similar to the base of the barrel as described.

The tongues 15 are elastic so that they can be separated so that the plunger 2 enters the barrel, the stop of said plate 22 against the tongue once it is between said tongue and the bottom of the barrel. will prevent the plunger from being withdrawn from the barrel.

As shown in Figure 5, when the conventional part of the plug 2 has a cruciform cross-section, there can be four tongues, each tongue being located in an empty quadrant formed by the plug.

Of course, the locking device can also have other different structures. For example, an annular cushion can be provided inside the cylindrical syringe 1 . To this end, the flange 19 of the cylindrical syringe 1 is left at the end of the syringe, which flange has a protruding inner ring inside the syringe, which is elastic so that after the injection plug 2 is inserted, the its pressed in.

After the syringe has been used once, it cannot be refilled in any way because the hub no longer ensures the seal of the plunger in the barrel.

To actually avoid re-use of the syringe, in addition to puncturing the hub to prevent aspiration of liquid, a means for destroying some part of the syringe may be provided.

For this purpose, close to the end plate 22, the syringe plug 2 has an annular groove 23, which narrows the syringe plug so that it can be broken off by the user after infusion. Once the broken part of the plunger 2 comes out to the outside of the barrel, it is impossible to move the remaining part with the socket 3 in the direction required for aspiration.

The manner in which the syringe is manufactured will be described below. The main thing is that the assembly should be done with great care in order not to puncture the fragile wall 34 .

In a first embodiment shown in Figure 6, the cylindrical barrel 1 is made in two parts: in front of the syringe, a shorter part 16, and another longer part 17, the shorter part comprising A base 13 and an end 14; the longer portion comprises a cylindrical tube with an open rear end and a flange 19 surrounding the rear end.

Claims (8)

1. A single-use syringe, comprising a cylindrical barrel (1) containing a plug (2) with a socket (3) in the shape of a hollow cylinder, which has the ability to ensure that it is compatible with the cylindrical Sealed peripheral wall of the barrel 1, closed front (31), and rear (32) with positioning pins (43) for securing the socket (3) to the drive needle (4) of the plunger (2) The hole (33) on the syringe is characterized in that: - the closing front (31) of the socket (3) has a breakable wall (34); - the back (32) of the socket has, in addition to the hole (33), at least another opening (35) outside the range of contact between the transmission needle (4) and the socket (3), which allows the socket ( 3) The inside communicates with the back chamber (12) of the cylindrical syringe (1); - The positioning pin (43) of the drive needle (4) for receiving the sleeve (3) has a drive needle (44) which pierces the breakable wall (34) when pushing the plunger in motion. 2. Syringe according to claim 1, characterized in that the drive needle (4) has a rod (41) connecting the positioning pin (43) to the end plate (22) of the plunger (2). 3. The syringe according to claim 2, characterized in that the length of the shaft (41) driving the needle (4) is substantially greater than the thickness of the sleeve (3), so that the sleeve (3) is between the following two positions Movement: In the first position, the back of the socket (32) is next to the cross-surface (42) of the positioning pin (43) of the transmission needle (4), and at this time, the suction force is exerted on the injection plug; and In the second position, the rear face (32) abuts the end plate (22), at which point the injection fluid is pushed out of the syringe. 4. The syringe according to claim 3, characterized in that, when the push force is applied to the liquid in the syringe through the injection plug, the driving needle (44) pierces the breakable wall (34), and the tightness of the sleeve tube depends on the end Sealing of the opening (35) by the plate (22) is ensured, while the driving needle (44) is at a distance from the breakable wall (34) when a pulling force is applied to the plunger in the retracted position. 5. The syringe according to claim 1, characterized in that the syringe has locking means (15) preventing retraction of the plunger (2) outside the cylindrical barrel (1). 6. The syringe according to claim 1, characterized in that the injection plug (2) has an annular groove (23) which can break the injection plug. 7. Syringe according to claim 1, characterized in that the cylindrical barrel (1) is made of two parts (16, 17) assembled to each other. 8. The syringe according to claim 1, characterized in that it is further provided with a stopper (18, 24) which completely prevents the movement of the plunger (2) as long as the user does not operate according to the working procedure.

Images