Patent Publication Number: US-2015065955-A1

Title: Syringe for the injection of a medicament with automatic needle extension and retraction

Description:
FIELD OF THE INVENTION 
     The present relates to a syringe for the injection of a medicament with automatic needle extension and retraction. 
     BACKGROUND 
     Currently, various syringe-type devices exist for the injection of a medicament, with automatic extension and retraction of the needle. 
     Patents U.S. Pat. No. 7,645,265B2 and U.S. Pat. No. 7,635,356B2 disclose an injection device which comprises an outer housing inside of which is located a barrel for holding a medicament M with a needle at one extreme thereof, the needle being capable of moving in and out of the housing, and a plunger or piston moveable inside said barrel, an inner housing intermediate the outer housing and the barrel and plunger, and an energy source in communication with said inner housing which causes the same to move between a first position where the needle is exposed outside the outer housing, a second position in which the medicament M is injected through the needle, and a third position in which the needle is retracted into the outer housing. 
     Patent U.S. Pat. No. 7,776,015B2 discloses a jet injector device which includes a chamber for the medicament M, with a needle having an injection end which extends from said chamber to be inserted into a patient using a force-generating source configured to apply a specific pressure to the chamber to expel the medicament M through the tip of the needle. 
     Patent EP1569708B1 discloses a catheter having a retractable needle and a tubular plunger supported by a structure in a preferred position before and during catheter insertion. Following the insertion of the same, the plunger is pushed permitting a compressed spring to force the needle upward into the plunger. 
     Publication EP2588174A1 discloses a medical device having a barrel, a retractable needle, a needle retraction assembly and a plunger, said assembly held inside the barrel prior to retraction and including at least in part a retainer member which is in contact with the barrel. The plunger comprises a seal and an elastomeric web which seals a retraction cavity inside the plunger prior to the retraction of the needle. The retainer member and the plunger seal each cooperate with an inside wall of the barrel to provide a sealed liquid containment chamber within the device. 
     Publication EP2349414A1 discloses a pre-filled syringe having a retractable needle with a variable volume liquid containment chamber defined by surfaces made of glass or an elastomeric material, but not plastic. 
     Patent U.S. Pat. No. 6,391,003B1 discloses a needle-assisted jet injector having a locking mechanism to reduce the probability of contact with the needle or the re-use of the same. When the force to expel the needle has been generated, one part of the needle extends beyond the injector nozzle and penetrates the outer layer of the patient&#39;s skin to deliver the medicament via jet injection to a deeper region. After the injection, the needle is retracted into the injector nozzle. 
     Publication U.S.2011/0015577A1 discloses a needle assembly which is used in combination with a storage device which comprises a barrel which defines a chamber which receives the medicament M and a piston, comprising an assembly one part of which supports the needle made of a first material said needle capable of moving between an exposed and concealed position, connecting elements to secure said needle-supporting part to said barrel in its exposed position. 
     Patent CN201481922U discloses a disposable injector having a replaceable needle head, which can be retracted and concealed after injection via an automatic retraction mechanism, which prevents the needle from being re-used. 
     Patent EP1567212B1 discloses a single-use retractable syringe which comprises a handle section and a needle retention section joined to said handle section which acts as a plunger and which further serves to activate the retraction mechanism when said handle section is extended beyond the injection position. The locking mechanism in the syringe barrel permits a rearward motion of the handle to fill the chamber with medicament, and a forward motion of the handle to empty said chamber, limiting the backward motion of the needle retention chamber and/or of the handle to prevent the syringe from being re-used even if the operator were to forget to activate the needle retraction device. 
     Patent U.S. Pat. No. 7,993,307B2 discloses a syringe having automatic and gradual retraction of the needle which includes a plunger inside a hollow barrel, a piston in the head of the plunger and a hub at the head of the barrel. The hub includes an elastic connecting hub which connects to the hub, and which can be disconnected from the head of the barrel and retracted by the action of a spring after the injection has been completed, so that the needle is retracted into the barrel. 
     Publication numbers EP2438943A1, EP2438942A1, EP2438947A1, AR083348A1, AR083345A1 and AR083346A1, disclose automatic injectors for administering medicaments, which comprise a tubular chassis and a carrier sub-assembly including a tubular carrier capable of displacement within the chassis. The carrier comprises a syringe, a drive spring and a plunger to positively load the spring when it moves forward until it reaches a stop element set into the syringe. A control spring is connected to the carrier by first locking devices for inserting the needle. Second locking devices are available in to release the drive spring when the carrier reaches the position for administering the medicament. The first locking devices disconnect the control spring from the carrier, and connect it to the chassis so that it will advance over the needle thus successfully concealing the same. 
     Document AR0010255A1 discloses a combined retractable needle and syringe in which the needle is mounted on a retractable element which retracts into the body of the syringe plunger. Said retractable element is driven by a spring, and is activated by releasing the front end of the retractable element from its coupling with a mount located at the front end of the inside barrel of the syringe. Said front end is only released when the mount is pushed forward, extended and is detached from the retraction element of the needle. 
     Publication AR003355A1 discloses a needle triggering device using a plastic element which when released by said triggering device, pushes the needle against the patient&#39;s skin. 
     Publication AR247486A1 discloses a syringe having an auto-disable needle which is lodged in a sheath with elastic means which permit its complete retraction into said sheath. 
     Patent AR236442 discloses a syringe which comprises a cylinder containing a plunger with a piston, said cylinder having mounted on it a sliding tubular protector which covers the entire length of the needle, including means for defining the position of said needle between at least two positions, one outside the protector and the other disabled within the same. 
     Publication AR006066A1 discloses a single-use, disposable syringe having an automatic safety mechanism, which is based on the structure of two cylinders and one plunger, all made of elastomeric or plastic material. The first cylinder is open at one of its extremes, covers the needle inside it and contains a spring, and the other extreme thereof has an aperture through which the needle exits at the moment of the injection. The second cylinder, smaller in diameter, terminates in a wall having a frustoconical protrusion and a central aperture which carries the needle and is also open at its other extreme, being able to slide longitudinally within the first cylinder. The plunger has a rubber piston at one of its extremes and slides through the inside of the second cylinder and the other extreme has a groove. Both cylinders and the plunger have cylindrical or ellipsoidal winglets for manipulating the syringe. The winglets have ratchet teeth or impediments on their surfaces which constitute the automatic safety mechanism. The second cylinder is inserted into the first cylinder, and because of the effect of the impediments, they become one single unit, permitting the needle to exit. When the plunger is pulled rearward inside the second cylinder, it is filled with the liquid which will be injected into the patient and the injection will occur by reversing the action. Once the injection has been completed, the safety mechanism definitively locks the plunger in the second cylinder, and the first cylinder returns to its position when the retaining ratchet is triggered once again covering the needle. 
     Publication AR011360A1, by the same Applicant, discloses a syringe having an automatically retractable needle, which comprises a drive piston, a containment cylinder with a needle-carrying head, and a needle with a coupling ring. 
     All of the devices presented above include a cylinder and a plunger, or two cylinders and a plunger, complicated to manufacture and manipulate, and do not have a complete sealing off mechanism. In this regard, the present invention simplifies the structure and the manipulation of this type of syringe by means of the inclusion of three coaxial cylinders where the third cylinder replaces said plunger, and includes a mechanism for automatic needle extension and retraction, completely sealing the path of the medicament. 
     SUMMARY 
     Thus the object of the present invention is a syringe for injecting medicament, having automatic extension and retraction of the needle, which comprises: 
     a first body with a cylindrical cross-section, which comprises a front end and a rear end; said front end is provided with a means of transport smaller in diameter than the first body, which is fastened to the same with a first fastening protrusion, said means of transport including a male frustoconical element which in turn includes conduits to transport said medicament, said front end further including a sealing protrusion and, located above said first fastening protrusion and said first sealing protrusion, a first alignment protrusion, inside said first body there is also a first elastic element which is fastened to said rear end of said first body with a posterior spring clip, and to said means of transport with an anterior spring clip, the rear end of said first body includes a handle; 
     a second body which has an front end and a rear end, this latter being open to allow said first body to be inserted, and provided with a stop element located inside the second body, said second body having at some point of its outer surface, a second fastening protrusion, said front end further including a second alignment protrusion, from the front end of said second body a frustoconical cavity projects which acts as a detent for the needle, from which a cylindrical space is provided concentrically, including grooves; and 
     a third body which further includes an front end and a rear end, open to permit the insertion of said second body, inside of which there is a flexible stop included which acts as an impediment to said second fastening protrusion of said second body, a release button being set above said flexible stop consisting of an anterior part at a right angle penetrating into said third body, and a posterior part linked to a second elastic element, said front end includes a third elastic element which is fastened to said third body via fasteners in the center of which there is an aperture whose diameter is approximately the same as that of the needle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description of the preferred embodiment of the present invention will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It is understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
         FIG. 1  shows a cross-section of the elements of the syringe according to the invention. 
         FIG. 2  shows a cross-section of the syringe according to the invention prior to the suction of the medicament M. 
         FIG. 3  shows a cross-section of the syringe according to the invention with the medicament M inside the second element. 
         FIG. 4  shows a cross-section of the syringe in a position prior to the injection of the medicament, with the needle concealed. 
         FIG. 5  shows a cross-section of the syringe according to the invention after the patient&#39;s skin has been punctured and at the point of injecting the medicament M. 
         FIG. 6  shows a cross-section of the syringe according to the invention during the injection of the medicament M. 
         FIG. 7  shows a cross-section of the syringe according to the invention after the injection of the medicament M and the retraction of the needle. 
         FIG. 8  shows an enlarged section defined in  FIG. 2  while the needle according to the invention is in its original position. 
         FIG. 9  shows an enlarged section defined in  FIG. 3 , during the process of taking the medicament M. 
         FIG. 10  shows an enlarged section defined in  FIG. 4  during the retraction of the needle. 
         FIG. 11  shows a first embodiment of the transport conduits for the medicament. 
         FIG. 12  shows a second embodiment of the transport conduits for the medicament. 
         FIG. 13  shows the moment of injection of the remaining medicament M once the transport conduits have been sealed. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a cross-section of the elements of the syringe according to the invention, where a first body A can be seen in cylindrical cross-section, which comprises an front end A 1  and a rear end A 2 . Said front end A 1  has a means of transport  9  of a lesser diameter than the first body A, which is fastened to the same by a first fastening protrusion  2 . Said means of transport  9  includes a male frustoconical element  1  capable of connecting under pressure with the female element of a needle  15  which will be located in a second cylinder B, as we will see below. Said front end A 1  also has a sealing protrusion  3  to prevent the medicament M from flowing upward. 
     Above said first fastening protrusion  2  and said sealing protrusion  3 , there is located a first alignment protrusion  4  which makes it possible to keep in the displacement of said first body A aligned inside said second body B as we will see below. Inside said first body A there is a first elastic element  5 , or spring, which is fastened to the rear end A 2  of the first body A with a posterior spring clip  6 , and to said transport medium  9  with an anterior spring clip  7 . The rear end A 2  of said first body A has a handle  10  whose diameter is greater than that of said first body A, and an ellipsoidal or circular configuration, suitable for being held by the operator during the loading of the medicament M. Said male frustoconical element  1  has, in turn, transport conduits for said medicament M. Said transport conduits can be configured with circular perforations O which go from the surface of said male frustoconical element  1  to a central longitudinal conduit  8  fabricated inside said male frustoconical element, such as shown in  FIG. 11 , for the longitudinal conduits  8 ′ made along the entire outside surface of said male frustoconical element  1 , as shown in  FIG. 12 , or for any other kind of conduit within the scope of any expert with ordinary skill in the art. 
     Said first body A is placed within a second body B, which also has an front end B 1  and a rear end B 2 , the latter being open to allow for the first body A to be inserted but with the presence of a stop element  18  located inside said second body B. Said stop element  18  comes into contact with said first alignment protrusion  4  of said first body A when it is being displaced rearward, the which permits the rearward displacement of said second body B. Said second body B includes at some point of its external surface a second fastening protrusion  11  which can take the form of a right-angled triangle or step, with its short side  11   a  being oriented towards said front end B 1 , forming a right angle with the external surface of said second body B. Said front end B 1  moreover, includes, a second alignment protrusion  12  which will keep the displacement of said second body B aligned inside said third body C as we will see below. From the front end of B 1  of said body B, a frustoconical cavity is projected which acts as a detent for a needle  15 , which prevents said needle from being displaced when it is triggered towards the body of the patient and when the ampoule which contains the medicament M is punctured, holding back said needle  15  until it receives sufficient traction force to remove it from said cavity  14 . 
     Concentrically and outward from said frustoconical cavity  14 , there is a cylindrical space  16 , which includes grooves  19  for adjusting half a turn a third elastic element  23 , or spring, present in a third body C as we will see below. Additionally, the anterior portion of the frustoconical cavity  14 , includes a membrane  17  which is penetrated by the needle  15 , to prevent the escape of any liquid. 
     Said second body B is inserted into a third body C which also includes an front end C 1  and a rear end C 2 , open to permit the insertion of said second body B. From that second rear end, there are winglets  28  projected radially outward to be grasped by the operator and included within it is a flexible stop element  26  which hinders the passage of the second fastening protrusion  11  of said second body B, indicating to the operator that he/she must stop with the withdrawal of said second body B, and at the same time permitting the operator, when the injection is finished, to withdraw said second body B from said third body C, hence its flexible characteristic. Above said flexible stop element  26 , a release button  22  is placed consisting of an anterior part  22   a  at a right angle which penetrates into said third body C, and a posterior part  22   b  linked to a second elastic element  24 . 
     When said second fastening protrusion  11  passes under said release button  22  during the rearward displacement of said second body B, said second elastic element  24  is compressed until it strikes said flexible stop element  26 , and said anterior part  22   a  of said release button  22  drops down in front of said base  11   a  of said second fastening protrusion  11  as a consequence of the pressure exercised by the decompression of said second elastic element  24 , locking the mechanism and readying the needle for insertion into the body of the patient. In said front end C 1  is a said third elastic element  23 , which is adjusted half a turn within said cylindrical space  16  via said grooves  19  in said second body B. Said third elastic element  23  is fastened to said third body C with fasteners  27  which have an aperture  29  in the center, approximately equal in size to the diameter of the needle  15  so that it can pass through the same. Said third body C can have a toy format and include colors if the patient is a child, so that the injection will not be traumatic. When the injection is completed, said third body C can be given to the child. The syringe assembly with the three bodies A, B and C can be seen in  FIG. 2 , where an enlarged area in a circle shows the interrelation of parts detailed in  FIG. 8 . 
     Said first body A serves as a plunger and as a means for automatic retraction of the needle  15 . Said second body B contains the medicament M and will retain said needle  15 . Said third body C permits inserting the needle into the patient, and can be separated from said second body B after the injection has been completed. 
     The operation of the syringe has 5 principal stages:
         1. to load the medicament M (see  FIG. 3 );   2. to conceal the needle (see  FIG. 4 );   3. to insert the needle into the patient (see  FIG. 5 );   4. to inject the medicament M (see  FIG. 6 );   5. to retract the needle (see  FIG. 7 ); and   6. to give the body C to the patient (this step is optional and not shown).       

     The medicament M is loaded in the traditional way by pulling rearward on said first body A, as shown in  FIG. 3 , where an enlarged area in a circle shows the interrelation of parts detailed in  FIG. 9 . Even if the medicament M has already entered said second body B, the operator continues to pull on said first body A until said release button  22  retains said second body B automatically within the third body C, as mentioned above. When the operator pulls rearward on said first body A, said second body B will also be displaced and both will encounter the stop elements. Specifically, said first body A is braked by said first alignment protrusion  4  in said stop element  18  of the body B, and said second fastening protrusion  11  of said second body B encounters said flexible stop element  26  of said third body C. 
     As mentioned above, said anterior part  22   a  of said release button  22  drops down in front of said base  11   a  of said second fastening protrusion  11  as a consequence of the pressure exercised in a downward direction by said third elastic element  24 , locking the second body B, which is then ready to inject as shown in  FIG. 4 , where an enlarged area in a circle shows the interrelation of parts detailed in  FIG. 10 . 
     The operator rests the anterior part of the syringe on the patient to proceed with the injection, at that moment the operator presses the release button to release said second body B, driving said needle  15  into the body of the patient, as shown in  FIG. 5 . Subsequently, the operator will inject the medicament M by pushing said first body A to the end, as shown in  FIG. 6 , and, with a slight additional pressure, said male frustoconical element will mate with said frustoconical cavity  14 . The transport conduits for said medicament M will permit the passage of the same, even after it has been sealed, however, some space will still remain to advance and complete the mating and adjust said male element  1  in said needle  15 . In other words, the medicament M remaining in body B, will pass via said transport conduits, reaching said needle  15  to be able to be injected into the patient as shown in  FIG. 13 . 
     On the one hand, the retraction of said needle  15  is achieved by a combination of forces, the mating of the male element  1  in frustoconical cavity  15  and the release of the means of transport  9 . The needle  15  will be released when the male element  1  captures it, and the transport means  9  released from the first fastening protrusion  2 , as shown in  FIG. 7 . As a consequence, said first elastic means  5  will begin to exert a much greater retractive force than the fastening force of said frustoconical cavity  14 . The frustoconical cavity  14  has a double function with respect to the needle  15 . 
     On the other hand, it holds the needle  15  so that it will not be dislodged from its place until it receives a specific force of traction, and on the other hand, its concave shape will not permit the needle  15  to move outward when the male element  1  enters into the needle  15  and exerts force on it until entering into the cavity under pressure. 
     Both in the case when the operator discards the syringe with the three bodies and also if he/she decides to give the third body C to a child, there are no risks of contamination either for the operator or for the child since the second body B is completely sealed making punctures or the exit of fluids impossible, and the third body C which the child gets is free of contaminants. 
     For transport and/or manipulation, the syringe includes a small plastic element (not shown) under the release button  22 , to prevent said release button  22  from being pressed accidentally. Said small plastic element can be easily removed when the operator deems it advisable. Another way of transporting the syringe is in a protective sleeve for the needle  15  (not shown), for which the anterior part C 1  of said third body C must include a corresponding fastening protrusion to fasten it to said protective sleeve for the needle  15 . 
     It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but is intended to cover all modifications which are within the spirit and scope of the invention as defined by the appended claims; the above description; and/or shown in the attached drawings.