Patent Publication Number: US-2013245564-A1

Title: Safety device for a syringe

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority of Taiwanese Patent Application No. 101108880, filed on Mar. 15, 2012. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a safety device for a syringe. 
     2. Description of the Related Art 
     As shown in  FIG. 1 , a conventional syringe  1  includes a cylinder body  11 , a needle unit  12  and a cover  13  for covering the needle unit  12 . The needle unit  12  includes a base seat  121  connected to the cylinder body  11 , and a cannula  122  extending from the base seat  121 . The cover  13  is elongated and is made of plastic. 
     The cover  13  is tightly fitted on the base unit  121  to enclose the cannula  122  therein to prevent the cannula  122  from wounding a medical personnel and being contaminated due to exposure to the air, and would be removed from the base unit  121  when the conventional syringe  1  is in use. After use of the conventional syringe  1 , the cover  13  has to be replaced to cover the cannula  122  before disposal the syringe  1 . 
     However, the medical personnel may be wounded by the cannula  122  due to misalignment of the cover  13  with the cannula  122  during the replacement of the cover  13 . 
     SUMMARY OF THE INVENTION 
     Therefore, the object of the present invention is to provide a safety device for a syringe to overcome the aforesaid drawback of the prior art. 
     According to this invention, the safety device is adapted to be sleeved on a needle unit of a syringe. The needle unit includes a base seat and a cannula that extends from the base seat along an axis. The safety device includes a barrel unit adapted to be movable along the axis with respect to the base seat of the needle unit of the syringe between an extended state, where the cannula is disposed within the barrel unit, and a retracted state, where the cannula extends outwardly of the barrel unit. The barrel unit has a connecting end portion that is adapted to be connected to the base seat, and a flexible end portion that is adapted to be distant from the base seat, that has a pair of coupling sections provided respectively with first and second engaging members, said flexible end portion being operable between an opened state, where the coupling sections define an opening that permits extension of the cannula when the barrel unit is at the retracted state, and a closed state, where the flexible end portion deforms to result in engagement between the first and second engaging members to thereby close the opening when the barrel unit is at the extended state. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment of this invention, with reference to the accompanying drawings, in which: 
         FIG. 1  is a fragmentary partly exploded perspective view of a conventional syringe; 
         FIG. 2  is an exploded perspective view of a preferred embodiment of a safety device for a syringe according to this invention; 
         FIG. 3  is an assembled perspective view of the preferred embodiment, illustrating a barrel unit at an extended state and coupling sections of a flexible end portion of the barrel unit at an opened state; 
         FIG. 4  is a sectional view of the preferred embodiment, illustrating the barrel unit at the extended state and the coupling sections of the flexible end portion of the barrel unit at the opened state; 
         FIG. 5  is another sectional view of the preferred embodiment, illustrating the barrel unit at a retracted state; 
         FIG. 6  is another assembled perspective view of the preferred embodiment, illustrating the barrel unit at the extended state and the coupling sections of the flexible end portion of the barrel unit at a closed state; 
         FIG. 7  is a fragmentary sectional view of the preferred embodiment, illustrating the coupling sections of the flexible end portion of the barrel unit at the closed state; and 
         FIG. 8  is another fragmentary sectional view of a modification of the coupling sections of the flexible end portion of the barrel unit. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in  FIGS. 2 and 3 , a preferred embodiment of a safety device according to this invention is adapted to be sleeved on a needle unit  2  of a syringe. The needle unit  2  includes a base seat  21  and a cannula  22  that extends from the base seat  21  along an axis (L). 
     The safety device comprises a barrel unit  3  that is movable along the axis (L) with respect to the base seat  21  between an extended state (see  FIGS. 3 and 4 ), where the cannula  22  is disposed within the barrel unit  3 , and a retracted state (see  FIG. 5 ), where the cannula  22  extends outwardly of the barrel unit  3 . The barrel unit  3  includes a base barrel  31 , an intermediate barrel  32  and a terminal barrel  33 . The base barrel  31  has a connecting end portion  311  that is adapted to be connected threadedly to the base seat  21  of the needle unit  2 . It should be noted that the connecting end portion  311  may have a part sleeved fittingly on the base seat  21 , or may be connected directly to a syringe body  25  to which the needle unit  2  is coupled. 
     The intermediate barrel  32  is sleeved slidably on the base barrel  31  and has a positioning end portion  321  adapted to be distant from the base seat  21  of the needle unit  2 . The positioning end portion  321  of the intermediate barrel  32  has an end wall  329  that is normal to the axis (L) and that is formed with a positioning hole  322  adapted for extension of the cannula  22  of the needle unit  2  during the movement of the barrel unit  3  between the retracted and extended states. 
     The terminal barrel  33  is sleeved slidably on the intermediate barrel  32  and has a flexible end portion  331  that is adapted to be distant from the base seat  21 . The flexible end portion  331  has a pair of coupling sections  331   a,    331   b  provided respectively with first and second engaging members  4 ,  5 , and is operable between an opened state (see  FIGS. 3 to 5 ), where the coupling sections  331   a,    331   b  define an opening  332  that permits extension of the cannula  22  when the barrel unit  3  is in the retracted state, and a closed state (see  FIGS. 6 and 7 ), where the flexible end portion  331  deforms to result in engagement between the first and second engaging members  4 ,  5  to thereby close the opening when the barrel unit  3  is in the extended state. 
     In this embodiment, the coupling sections  331   a,    331   b  are integrally and respectively formed with the first and second engaging members  4 ,  5 . The first engaging member  4  is a first coupling groove  41 , and the second engaging member  5  is a first coupling protrusion  51 . In other embodiments of this invention, as shown in  FIG. 8 , the first and second engaging members  4 ,  5  may be adhered on the coupling sections  331   a,    331   b,  while the first engaging member  4  is formed with the first coupling groove  41 , and the second engaging member  5  is formed with the first coupling protrusion  51 . Moreover, the first and second engaging members  4 ,  5  may be configured as soft magnets. 
     Each of the base barrel  31  and the intermediate barrel  32  has an outer surface formed with a pair of guiding grooves  313 ,  328  extending in the direction of the axis (L). Each of the intermediate barrel  32  and the terminal barrel  33  has an inner surface formed with a pair of guiding protrusions  327 ,  334  that engage slidably and respectively the corresponding guiding grooves  313 ,  328  of a respective one of the base barrel  31  and the intermediate barrel  32 . The positioning end portion  321  of the intermediate barrel  32  is formed with a second coupling groove  324  and a second coupling protrusion  325 . 
     The outer surface of each of the base barrel  31  and the intermediate barrel  32  is formed with an annular positioning groove  312 ,  323  at a position distal from the base seat  21 . The inner surface of each of the intermediate barrel  32  and the terminal barrel  33  is formed with an annular positioning protrusion  326 ,  333  that is approximate to the base seat  21 . Moreover, the second coupling groove  324  and the second coupling protrusion  325  of the intermediate barrel  32  are disposed between the positioning groove  323  and an end edge of the positioning end portion  321 . 
     As shown in  FIG. 4 , when the barrel unit  3  is at the extended state, the positioning protrusion  326  of the intermediate barrel  32  engages removably the positioning groove  312  of the base barrel  31 , while the positioning protrusion  333  of the terminal barrel  33  engages removably the positioning groove  323  of the intermediate barrel  32 , thereby positioning the base barrel  31 , the intermediate barrel  32  and the terminal barrel  33  with one another. Further referring to  FIG. 5 , in use of the syringe, the terminal barrel  33  is moved toward the base seat  21  to move the barrel unit  3  telescopically from the extended state to the retracted state. During the movement of the barrel unit  3  from the extended state to the retracted state, the terminal barrel  33  and the intermediate barrel  32  can move stably without rotation about the axis (L) by virtue of the engagements between the guiding protrusions  327 ,  334  and the guiding grooves  313 ,  328 . When the barrel unit  3  is in the retracted state, the second coupling groove  324  and the second coupling protrusion  325  of the intermediate barrel  32  are engaged respectively with the first coupling protrusion  51  and the first coupling groove  41  of the base barrel  31 . After use, the barrel unit  3  is moved from the retracted state to the extended state, and the flexible end portion  331  of the terminal barrel  33  is squeezed from the opened state to the closed state before disposal of the syringe. 
     To sum up, the barrel unit  3  can effectively protect a medical personnel from being wounded by the cannula  22 , and is not required to be removed during use of the syringe. 
     While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation and equivalent arrangements.