FR2814371A1 - Safety syringe for injection of any medical liquid, comprises hollow tubular needle sleeve that is put around cap of the syringe - Google Patents

Abstract

Safety syringe has a needle sleeve in a form of a hollow tube that is put around a cap of the syringe into which a hub is tightly fitted, such that the hub is allowed to temporarily locate closely before, but not engaged into a neck portion of a barrel of the syringe. Safety syringe has a barrel (A) having a diameter-reduced front neck portion, a plunger (B) slidably mounted in the barrel, a hub (C) at a front end of the barrel for holding a cannula (C1), and a cap (D) into which the hub is tightly fitted. It has a needle sleeve (1) in a form of a hollow tube that is put around joints of the hub and the neck portion of the barrel and of the hub and the cap. A front part of the inner space of the needle sleeve has a reduced inner diameter. An inner peripheral wall of this front part is tapered toward a front end of the syringe, and an inner peripheral wall of the rear part is tapered toward the front end of the syringe, such that a first shoulder portion is formed between the front and rear inner peripheral walls. The first shoulder portion abuts on a radially outward projected flange around a rear end of the cap, and a part of the rear inner peripheral wall surface of the needle sleeve contacts with an outer peripheral wall of the diameter-reduced neck portion of the barrel in a tight fit manner, allowing the hub to locate closely before a front open end of the neck portion without being engaged into and retained to the neck portion. When the cap is depressed, the hub is moved backward into and retained to the neck portion of the barrel by a second shoulder portion inside the neck portion. When the cap is pulled forward again and the rear flange of the cap abuts against the first shoulder portion inside the needle sleeve, the needle sleeve and the cap are removed from the hub to expose the cannula for injection.

Description

SAFETY SYRINGE WITH A NEEDLE SLEEVE

  In the medical world of yesteryear, it was customary to sterilize syringes thoroughly after use for later reuse. Insufficient sterilization then risked re-infection of a patient and possibly others. To avoid such re-infection, large quantities of disposable syringes are being produced at present. However, large numbers of discarded disposable syringes present new problems in terms of environmental pollution and the safety of the syringes used. This is due to the fact that no specific measures have been taken to dispose of the hollow needles of the discarded syringes; in addition, exposed hollow needles can easily injure caregivers or cleaners, further increasing the number of people infected. This is why many safety syringes have been specially developed. U.S. Patent No. 5,562,627; 5,405,327; 5,569,203; , 899.887; 5,395,346, etc. all disclose safety syringes with associated tips and bodies, as well as retractable bodies, such that the tips and hollow needles of used syringes can be retracted into the bodies without risk of unforeseen injury other

people.

  However, all of these safety syringes of the prior art developed to perfect conventional syringes present a common problem, namely that the tips of these safety syringes must be able to be stably connected to the bodies and be retracted inside. the latter after the use of syringes, and that the tips must be connected to the bodies in a completely airtight manner, which requires solutions of a high level of technicality. As is known, when these safety syringes are assembled during the manufacturing process, the tips and the bodies must, as a first step, be joined together before sterilization of the syringes, so that the assembled syringes cannot not be contaminated after sterilization due to contact with any part of the syringes. However, the tips and assembled bodies are subjected to stress deformations and thermal deformations during high temperature sterilization and these deformations can have an undesirable effect on the stability and air tightness of the joint between the tips. and bodies. The inventor therefore attempted to develop an even more sophisticated safety syringe to eliminate the disadvantages inherent in syringes.

  safety of prior techniques.

  A main object of the present invention is to provide a safety syringe with a needle sheath which has been particularly designed to improve a conventional safety syringe with retractable tip. The needle sheath of the safety syringe of the present invention makes it possible to sterilize the syringe with its tip and its body in contact but not in engagement, 1: 5 so that no deformation occurs under stress or any thermal deformation of the syringe likely to adversely affect the stability and air tightness of the seal between the tip and the body of the syringe after

sterilization.

  Another object of the present invention is to provide a safety syringe with a needle sheath, in such a way that the needle sheath keeps the cap, the nozzle and the body of the syringe firmly united, which makes it possible to '' isolate the hollow needle and tip from the external environment and protect them from contamination due to any external contact of the hollow needle before using the syringe for injection. The needle sheath also allows for easy engagement of the tip

  on the body of the safety syringe by simply pressing the cap.

  Yet another object of the present invention is to provide a safety syringe with a needle sheath. The needle sheath has two stops on an inner wall against which a posterior end of the cap abuts, preventing the cap from being undesirably pressed to cause undesirable engagement of the tip with

  the body before the syringe is used for an injection.

  The structure and technical means adopted by the present invention to achieve the above objectives as well as others will be better

  understood if reference is made to the following detailed description of the embodiments

  preferential as well as to the appended diagrams, in which: FIG. 1 is an exploded perspective view of a safety syringe with a needle sheath according to a first embodiment of the present invention, and FIG. 1A is a view in vertical section of the sheath or needle illustrated in Figure 1; - Figure 2 is an exploded perspective view of a safety syringe with a needle sheath according to a second embodiment of the present invention; - Figure 3 is a vertical sectional view of the needle sheath illustrated in Figure 2, and Figure 3A is a cross-sectional view of the needle sheath of Figure 3, taken on the axis A-A; - Figure 4 is a sectional view of a tip and a cap of the safety syringe of the present invention in an assembled state; - Figure 5 is an enlarged and fragmented sectional view of the first embodiment of the safety syringe of the present invention, which illustrates the method of assembling the tip, the cap and the needle sheath, the tip not having been engaged in a neck portion of a body of the safety syringe; - Figure SA is an enlarged and fragmented sectional view of the second embodiment of the safety syringe of the present invention, which illustrates the method of assembling the tip, the cap and the needle sheath, the tip not having been engaged in a neck portion of a body of the safety syringe - Figure 6 is a sectional view similar to Figure 5 but in which the tip is retained by the neck portion of the body the safety syringe of Figure 1; - Figure 6A is a sectional view similar to Figure 5A but in which the tip is retained by the neck portion of the body of the safety syringe of Figure 2; - Figure 7 illustrates the mode of withdrawal of the cap and the needle sheath relative to the tip and the body of the safety syringe of Figure 1; - Figure 7A illustrates the mode of withdrawal of the cap and the needle sheath relative to the tip and the body of the safety syringe of Figure 2; - Figure 8 illustrates the engagement of a plunger of the safety syringe of the present invention with the tip when the plunger has been pushed as far forward in the body; - Figure 9 illustrates the tip and the hollow needle of the safety syringe of the present invention when pulled back by the piston in the body after the hollow needle has been used; FIG. 10 illustrates a needle sheath and a cap 20 for a safety syringe according to a third embodiment of the present invention. The present invention relates to a retractable safety syringe, the elements of which mainly comprise a body A, a piston B which is slidably mounted in the body A, a nozzle C connected to an anterior end of the body A for carrying a needle Hollow Cl, and a cap D to cover the hollow needle CI. Any structure of these elements which is

  similar to that of a conventional safety syringe will not be repeated here.

  The safety syringe of the present invention is characterized by a needle sheath and structures of other elements of the syringe which cooperate with the needle sheath. The needle sheath is placed around the joints between the tip C and the body A and between the tip C and the cap D, as can be

  see clearly in Figures 5 and SA.

  Figure 1 is an exploded perspective view of a safety syringe with a needle sheath 1 according to a first embodiment of the present invention. As can be seen from FIG. 1A, the needle sheath 1 is a hollow tube which defines an interior space inside. An anterior part of the interior space of the needle sheath 1 has a reduced interior diameter. And, an inner peripheral wall 12 of this front part has a suitable conical shape narrowing towards an anterior end of the safety syringe, that is to say an end with the hollow needle C1. A posterior part of the inner space of the needle sheath 1 has an inner diameter greater than that of the front part, and an inner peripheral wall 13 of the rear part also has a suitable conical shape narrowing towards the front end of the safety syringe. Thus, a first shoulder portion 1 1 is formed between the inner peripheral wall 12 and the wall

inner ring 13.

  As illustrated in FIG. 1, the end piece C comprises, near its middle part, a second shoulder part C2, and in a rear part, two diametrically opposite engagement holes C3. The body A has a reduced diameter neck portion A2 which defines an anterior open end of the body A. An inner peripheral wall Ai of the anterior open end of the neck portion A2 is inclined radially inward. And, a third shoulder portion A3 is formed between the inclined peripheral wall A1 and a substantially cylindrical inner peripheral wall of the neck portion A2

  2 5 behind the open inner end of the neck portion A2.

  To assemble the safety syringe of this first embodiment, it is first necessary to thread the tip C and the hollow needle Ci connected to the latter into the cap D. The cap D is designed so that its inside diameter corresponds to the outside diameter of a part of the end piece C above the second shoulder portion C2, which allows the end piece C to be closely adapted in the cap D to form a needle assembly such that 'illustrated in the figure. 4. Next, the needle sheath 1 is placed around the needle assembly from the anterior end of the cap D, so that the first shoulder portion 11 1, inside the sheath d needle 1, comes into abutment against a rear collar D2 of the cap D. At this point, a rear end portion of a surface Dl of the external peripheral wall having a conical shape narrowing towards the front and the rear collar D2 of the cap D are in close contact with the anterior and posterior interior peripheral walls 12 and 13 respectively of the needle sheath 1, the first shoulder part 11 abutting against the collar D2. The needle assembly and the needle sheath 1 placed around it therefore form a needle sheath assembly. As can be clearly seen from Figure 5, the tip C is completely covered by the needle sheath 1 and isolated from the external environment and, therefore, any contamination possibly by unwanted contact of the needle hollow C1. The needle sleeve assembly is then assembled to the body A by engaging the inner peripheral wall 13 of the rear part of the needle sleeve 1 with an outer peripheral wall of the reduced neck part A2 of the body A, as illustrated in FIG. 5, to form a syringe assembly, that is to say the safety syringe according to the first embodiment of the present invention. Before being used to inject a medical liquid, this syringe assembly has a nozzle C provided with a posterior lower part in contact with the inclined inner peripheral wall AI at the anterior open end of the neck part A2 of the body A without being engaged in or retained in the A2 neck portion. The syringe assembly is

  then sterilized at high temperature in this state.

  Since the tip C is not engaged to the maximum inside the neck portion A2 of the body A nor retained in it when the syringe assembly is sterilized at high temperature, no solicitation will be produced at this stage of sterilization. Therefore, it becomes possible to avoid any deformation by solicitation and any thermal deformation of the syringe as a whole.

  made of such high temperature sterilization.

  To use the syringe assembly for the injection of any medical liquid, a user can press on an anterior end of the cap D, so that the tip C tightly housed in the cap D moves downward simultaneously. When the second shoulder part C2 of the end piece C is moved downwards beyond the surface A1 of the peripheral wall inclined radially inward and the third shoulder part A3 of the anterior open end of the part with neck A2 of body A, the end piece C can no longer be pulled again forwards to be separated from the body A. At this point, an outer peripheral wall surface of the rear part of the end piece C, behind the second shoulder part C2, will come into contact with the cylindrical inner peripheral wall surface of the neck part A2 behind the third shoulder part A3 in a tight fit, as illustrated in FIG. 6, which makes it possible to obtain airtightness at the joint between the nozzle C and the body A. Finally, the cap D is pulled forward to expose the hollow needle Cl. In doing so, the rear collar D2 of the cap D will die place to abut against the first shoulder portion 11 inside the needle sheath 1, so that the needle sheath 1 simultaneously separates from the tip C, as illustrated in Figure 7. After that the cap D and the needle sheath 1 were removed to expose the hollow needle CI, the safety syringe

  according to the first embodiment of the present invention is ready for use.

  When the safety syringe according to the first embodiment of the present invention is used to inject a medical liquid into a patient, the piston B is pushed all the way forward into the body A until a engagement cone B2 provided at an anterior end of the piston B engages with the engagement holes C3 provided on the rear portion of the nozzle C, as illustrated in Figure 8. After injection, the piston B can be pulled back to move back into the body A the tip C, which is now associated with the piston B, and the hollow needle C1, which is connected to the tip C, as illustrated in

Figure 9.

  Figure 2 is an exploded perspective view of a retractable safety syringe with a needle sheath 1 'according to a second embodiment of the present invention. The needle sheath 1 'is similar to the needle sheath 1 except that it is provided with means which prevent the cap D from being undesirably pushed in. FIGS. 3 and 3A respectively illustrate vertical and transverse sections of the needle sheath 1 ′. All the parts of the needle sheath 1 'similar to those of the needle sheath 1 are indicated by the same reference numbers. The means, on the needle sheath 1 ', which prevent the cap D from being undesirably pressed include two diametrically opposite square through holes 14 formed in the rear part of the needle sheath 1', immediately behind the first part with shoulder 11. Two zones of the inner peripheral wall 13 respectively immediately adjacent to the rear edges of the holes 14, protrude radially inwards to form two first stops 15. The safety syringe of this second embodiment comprises a tip D 'similar to the cap D of the first embodiment, but which has two second stops D2' provided on the rear end thereof, to replace

2 0 the rear collar D2.

  The body A, the piston B, the nozzle C and the hollow needle Cl of the safety syringe of the second embodiment, as well as the assembly of these elements, are similar to those of the first embodiment, such

  as illustrated in FIGS. 4, 5A, 6A, 7A, 8 and 9.

  The needle sleeve 1 'is placed around the needle assembly from an anterior part of the cap D', so that the second stops D2 'are behind the first shoulder part 11 inside the sleeve needle 1 'and before the first stops 15, to prevent

  the cap D 'to move rearward relative to the needle sheath 1'.

  FIG. 10 illustrates a needle sleeve 1 "and a cap D 'for a retractable safety syringe according to a third embodiment of the present invention. The needle sleeve 1" is structurally similar to the needle sleeve 1' except that it has two third stops 15 'which extend axially separately from one end of the first stops 15 towards an anterior end of the needle sleeve 1 ". The second stops D2' on the cap D ' end up coming to abut against the two third stops 15 'when the cap is subjected to a rotation to place the second stops D2' between the first shoulder portion 11 and the first stops 15. The

  third stops 15 'limit the rotation of the cap D'.

  In fact, the adjusted contact between the surface D 1 'of the outer peripheral wall of the cap D', which has a conical shape narrowing towards the front, and the anterior inner peripheral wall 12 of the needle sheath 1 'proper allows the cap D 'and the needle sheath 1' to be stably connected to each other without risk of relative rotation one by

  relative to each other, unless an external force is applied to rotate them.

  Thus, the cap D 'and the needle sheath 1' can remain connected

  stably, even in the absence of the third stops 15 '.

  To improve the stability of the connection between the needle sleeve 1 'and the cap D', it is also possible to provide the first stops 15 and the second stops D2 'with contact surfaces inclined to each other, so that the 'closeness of the contact between the cap D' and the needle sheath 1 'increases with a degree of rotation of the cap D' relative to the sheath

needle 1 '.

  In the two abovementioned embodiments, the cap D 'is turned counterclockwise to separate the second stops D2' from the first stops 15, after which it is possible to push the cap D 'to

  firmly assemble the tip C to the body A for injection.

  With the arrangements described above, the safety syringe of the present invention is sterilized at high temperature before the tip C is tightly housed in the front neck part A2 of body A. Therefore, it is possible to avoid any deformation by stress or thermal deformation at the joint between the tip and the body of the syringe, deformation possibly caused by such sterilization at high temperature. Therefore, the safety syringe can still maintain a good air seal at this seal. In addition, the needle sheath 1 protects the tip C and the body A of the safety syringe against any contamination due to unwanted contact of the tip before use. In the second and third embodiments, the stops 15 and D2 'serve as securing elements to prevent

  l0 still more the cap to be undesirably pressed.

  The safety syringe with a needle sheath of the present invention is therefore more improved than the safety syringes

  and is practical to use.

Claims (4)

  1 / - Safety syringe with a needle sheath, comprising a body (A) having a neck portion (A2) anterior of reduced diameter, a piston (B) slidably mounted in said body (A), a nozzle (C) placed at an anterior end of said body (A) to carry a hollow needle (C 1), and a cap (D) in which said tip (C) is tightly housed so that said hollow needle is covered and protected by said cap (D), said safety syringe being characterized in that it comprises a needle sheath (1, 1 ') which is placed around the joints between said end piece (C) and said neck part (A2 ) of said body (A) and between said end piece (C) and said cap (D); said needle sheath (1, 1 ') being a hollow tube delimiting inside an interior space, an anterior part of said interior space of said needle sheath (1, 1') having a reduced internal diameter, and a wall inner device (12) of this anterior part having a conical shape narrowing towards an anterior end of said safety syringe, that is to say, an end with said hollow needle (Cl), and a posterior part of said interior space said needle sheath (1, 1 ') having an inner diameter greater than that of said anterior part, and an inner peripheral wall (13) of the posterior part having a conical shape narrowing towards the anterior end of said syringe safety, so that the needle sheath (1, 1 ') has a first shoulder portion (11) between said anterior inner peripheral wall (12) and ladi the rear inner peripheral wall (13); and said needle sheath (1, 1 ') being placed around said nozzle (C) and said cap (D) from a front end of said cap (D), so that said first shoulder portion (11) the interior of said needle sheath (1, 1 ') abuts against a collar (D2) projecting radially outward around a rear end of said cap (D) and so that part of said rear inner peripheral wall surface (13) of said needle sheath (1, 1 ') closely matches an outer peripheral wall of said neck portion (A2) of reduced diameter of said body (A) allowing said end piece (C) to be arranged immediately in front of an open front end of said neck part (A2) without being engaged in or retained in said neck part (A2) so that, when said cap (D) is pressed, said end piece ( C) tightly housed in said cap (D) is brought to move backwards in said neck part (A2) of said body (A) and to be retained there by a second shoulder part (C2) inside said neck part (A2), and when said cap (D) is again pulled forward and said rear collar (D2) of said cap (D) abuts against said first shoulder portion (11) inside said needle sheath (1, 1 '), said needle sheath (1, 1 '), as well as said cap (D), are separated from said tip (C) and removed to expose said hollow needle (C1) for injection. 2 / - Safety syringe with needle sheath (1 ') according to claim 1, wherein said needle sheath (1') is provided, immediately behind said first shoulder portion (11), with two square through holes (14) diametrically opposite and separate zones provided on said rear inner peripheral wall (13), immediately adjacent to the rear edges of said two square through holes (14), and extending radially inwardly projecting to form two first abutments (15); and said collar (D2) of said cap (D) being replaced by two second stops (D'2), so that, when said needle sheath (1 ') is placed around said nozzle (C) and said cap ( D ') from a front end of said cap (D'), said second stops (D'2) on said cap (D ') abut against said first stops (15) in said needle sheath (1') for preventing said cap (D ') from being undesirably pressed; and, when said syringe is to be used for an injection, it is possible to subject said cap (D ') to rotate in order to move said second stops (D'2) from said first stops (15) so that said cap (D') can be pushed in, thus pushing said end piece (C) which it closely follows in said neck portion (A2) of said   body (A), in which said tip (C) is retained.   3 / - Safety syringe with a needle sheath (1 ") according to claim 2, wherein said two first stops (15) are each provided, at one end, with third stops (15 ') which extend axially and towards the front, and against which one end of said second stops (D'2) on said cap (D ') abuts, so as to limit the rotation of said cap (D')   relatively to said needle sheath (1 ").   4 / - Safety syringe with a needle sleeve (1 ', 1 ") according to claim 2, wherein said first (15) and said second stops (D'2) have contact surfaces inclined to each other to make possible close contact between them by rotation of said cap (D ') relative to said needle sleeve (1, 1 ").