Abstract:
A disposble rectractable-needle syringe comprises a cylindric body including a first end for engaging therein a piston element and a second end having an attachmen for a needle assembly. The piston element comprises latching means for latching the needle assembly and allowing the needle to be introduced into the cylindric body upon ending the injection operation, by operating the piston element. The latching means comprise one end of the gasket applied to the piston, designed for receiving hook means included in the needle assembly.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a disposable retractable-needle syringe.  
           [0002]    As is known, in using hypodermic needles, it is absolutely necessary to prevent a needle from transmitting infective diseases.  
           [0003]    In fact, the syringe needle may contact the skin of the sanitary operator, and this also due to a repeated use of the syringe.  
           [0004]    Several approaches have been submitted to reduce the problems related to the disposal of disposable syringes and from preventing said disposable syringes-from being reused.  
           [0005]    Among the proposed approaches, retractable needle syringes have been designed, in which, upon use, the syringe needle is withdrawn into the syringe cylindric body, by resilient means.  
           [0006]    Such a syringe, however, has the drawback that it cannot be used by conventional methods, since it compels the operator to overcome the counter-biassing force of the mentioned resilient means in performing the injection operation.  
           [0007]    Another drawback is that said syringes have a comparatively high cost, due to their constructional complexity.  
           [0008]    Yet other types of disposable syringes comprise collapsable coupling means connecting the syringe needle to the syringe cylindric body; on the other hand, it has been found that these latter syringes are scarcely reliable in operation.  
         SUMMARY OF THE INVENTION  
         [0009]    Accordingly, the aim of the present invention is to provide a disposable retractable-needle syringe, which is adapted to overcome the above mentioned drawbacks of prior retractable-needle syringes.  
           [0010]    Within the scope of the above mentioned aim, main object of the present invention is to provide a disposable syringe including a retractable needle, specifically designed for preventing said syringe from being reused, and which is constructionally very simple and very inexpensive from a mere making standpoint.  
           [0011]    A further object of the present invention is to provide a retractable needle disposable syringe, which does not include any resilient elements, and which can be used in a manner fully like to that of a conventional syringe.  
           [0012]    Yet a further object of the present invention is to provide such a disposable retractable-needle syringe, the components of which can be assembled by automatic assembling apparatus, thereby minimizing any manual operations by human operators, and which, moreover, has very good hygienic characteristics.  
           [0013]    Yet a further object of the present invention is to provide such a disposable retractable-needle syringe which can be made by conventional elements used for making conventional syringes, possibly with very simple modifications allowing to use conventional syringe molding apparatus and molds.  
           [0014]    According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a disposable retractable-needle syringe, comprising a syringe body including a first end for engaging therein a piston element and a second end including an attachment for a needle assembly, characterized in that said piston element comprises latching means for latching said needle assembly, designed for allowing the syringe needle to be introduced into said cylindric body upon ending an injection operation, by operating said piston element.  
           [0015]    The latching means comprise one end of the gasket of the piston element, designed for receiving hook means provided in the needle assembly. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred, though not exclusive, embodiment of the invention, which is illustrated, by way of an indicative, but not limitative, example, in the accompanying drawings, where:  
         [0017]    [0017]FIG. 1 is an exploded view of the disposable retractable-needle syringe according to the present invention;  
         [0018]    [0018]FIG. 2 is an enlarged partial view of that same disposable retractable-needle syringe, being shown in a piston feeding operation thereof, said piston having a gasket to which is applied an insert element including teeth designed for latching the needle assembly;  
         [0019]    [0019]FIG. 3 is a view analogous to FIG. 2, in which the syringe is shown at the end of stroke position of the syringe piston in which the needle has been latched;  
         [0020]    [0020]FIG. 4 is a further schematic view of the disposable retractable-needle syringe according to the present invention, shown in a piston feeding operation, said piston being provided with a gasket in which are directly formed the needle latching teeth or annular elements;  
         [0021]    [0021]FIG. 5 is a view similar to FIG. 4, in which the syringe is illustrated in an end of stroke position of the piston with the needle in a latched condition;  
         [0022]    [0022]FIG. 6 is a further schematic view illustrating the syringe as the syringe piston is rearward driven with the needle latched thereto;  
         [0023]    [0023]FIG. 7 is a further schematic view illustrating the syringe with the syringe needle fully withdrawn and the piston being broken;  
         [0024]    [0024]FIG. 8 is a further schematic view of the disposable retractable-needle syringe, according to a further aspect of the present invention, being shown during a piston feeding operating step; and  
         [0025]    [0025]FIG. 9 is a schematic view similar to FIG. 8, in which the syringe of FIG. 8 is shown in an end of stroke position of the piston with the needle being latched. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    With reference to the number reference of the accompanying drawings, the disposable retractable-needle syringe according to the present invention, generally indicated by the reference number  1 , comprises a syringe cylindric body  2 , having a first end  3 , for engaging therein a piston element  4 , and a second end  5  including an end-piece  6  operating as an attachment element for a needle assembly  7 .  
         [0027]    Advantageously, at said first syringe end  3  is provided a narrowed region  23 , preventing the piston element  4  from being disengaged from the cylindric body.  
         [0028]    The cylindric body  2  and piston element  4  can have any conventional configuration, without any specifically designed constructional modification, with respect to the same components of a conventional syringe.  
         [0029]    The needle assembly  7  comprises a needle  8 , including an end portion opposite to the tip coupled to a small cylinder  9 .  
         [0030]    The latter comprises resilient wings  10 , each of which is provided with an outer cut-out  11 , designed for defining a latching tooth element  12  and an abutment  15 .  
         [0031]    The needle assembly  7  comprises a cap  13 , for holding therein said elements and engaging the end-piece  6  of the cylindric body  2  in order to lock the needle assembly  7  at a set use position thereof.  
         [0032]    The inner portion of the end-piece  6  comprises an annular step portion  14 , designed for engaging the abutment  15  of the wings  10  to counter-bias the pushing force generated during the injection operation and for holding the needle at the use position thereof, and for preventing said needle from being accidentally withdrawn.  
         [0033]    The piston element  4  comprises a stem  16 , including an attachment  17  for a sealing gasket  18 ,  118 .  
         [0034]    According to one aspect of the present invention, the sealing gasket  18  comprises a rubber element including annular ridges  19  designed for providing a sealing relationship with the inner wall of the cylindric body  2 , in a per se known manner.  
         [0035]    The sealing gasket  18  is hollow and is adapted to engage the attachment element  17  and restrain an insert  20 , having an end portion  21  projecting from a hole  22  formed in the gasket  18 .  
         [0036]    Said end portion  21  is provided for receiving the teeth  12  of the wings  10  of said needle assembly  7 .  
         [0037]    According to a modified embodiment of the invention, the sealing gasket  118  comprises a rubber element including annular ridges  119  for sealing against the inner wall of the cylindric body  2 , in a per se known manner.  
         [0038]    The sealing gasket  118  is hollow, and is designed for engaging the attachment element  17  and being provided with an end portion  121  for engaging therein and latching the teeth  12  of the wings  10  of said needle assembly  7 .  
         [0039]    [0039]FIGS. 4, 5 and  6 ,  7  illustrate operating steps for using the syringe according to the present invention, which is suitable to perform an injection operation by applying, in a conventional manner, a pressure on the piston element  4 , with a consequent delivery of the product or medicament to be injected.  
         [0040]    Upon ending the delivery operation, the end portion  21 ,  121  of the gasket applied to the piston  4  will engage said resilient wings  10  of the needle assembly, by clamping them and thereby disengaging the abutment  15  of the wings from the annular step portion  14  of the cylindric body.  
         [0041]    Thus, the needle assembly will be engaged by the gasket or inserts of the gasket applied to the piston.  
         [0042]    By withdrawing the piston element (FIG. 6), the needle is withdrawn inside the cylindric body and, as it has been fully withdrawn inside said cylindric body, it will assume an inclined position (FIG. 7), due to a difference of the two cut-outs  11  of the wings  10 .  
         [0043]    Thus, any further pressure applied to the piston  4  will not be able of further withdrawing the needle.  
         [0044]    As the piston  4  is arranged outside the cylindric body  2 , it would be moreover possible to break said piston, owing to the provision of suitable notches  24 , thereby further preventing any possible reuse of the syringe.  
         [0045]    The subject syringe is:characterized in that the needle  8  is rigid with the small cylinder  9  and resilient wings  10 , which latter project outward, in an opposite direction.  
         [0046]    Said resilient wings  10 , in particular, are provided with opposite cut-outs  11 , thereunder it is possible to see latching teeth  12  outward projecting and having a contour designed for spreading apart and engaging suitable teeth  21  inward projecting, rigid with an insert  20  coupled to a sealing gasket  18 ,  118 , in turn provided with annular ridges  19 ,  119  for providing a sealing relationship against the inner wall of the cylindric body  2 .  
         [0047]    Alternatively, and as is shown in FIGS. 4 and 5, the sealing gasket  140  could be provided with an end portion  121  for directly engaging and latching the teeth  12  of the resilient wings  10 .  
         [0048]    The disposable syringe according to the present invention comprises a needle assembly  7  including a cap  13  for holding said small cylinder  9  having resilient wings  10 , and designed for engaging the end-piece  6  of the cylindric body  2  for locking at a use position the needle assembly  7 .  
         [0049]    At this time, the syringe cannot be further used, and the syringe needle will be fully withdrawn inside the cylindric body.  
         [0050]    Thus, the syringe can be safely handled and disposed of.  
         [0051]    It has been found that the invention fully achieves the intended aim and objects.  
         [0052]    Actually, a disposable retractable-needle syringe has been provided, which can be made by substantially using existing syringe making apparatus, already used for making conventional syringes.  
         [0053]    A further advantage of the invention is that the subject syringe can be assembled by automatic assembling machine, thereby providing a perfectly hygienic product, in addition to a much higher production yield.  
         [0054]    The disposable retractable-needle syringe according to the present invention is susceptible to several modifications and variations, all of which will come within the scope of the inventive idea.  
         [0055]    All the constructional details can be replaced by other technically equivalent elements.  
         [0056]    In practicing the invention, the used materials, and the contingent size and shapes, can be any, according to requirements and the status of the art.