Abstract:
A retractable syringe is disclosed. The syringe includes a cap, a hub cover, a hub bottom, a gasket, a plunger and a barrel. Medicine for injection is placed within the barrel to proceed with an injection. After the injection is carried out by pulling back the plunger, an engaging button linked to the hub cover and hub bottom is pulled down and the needle mounted at the hub cover is hidden within the barrel. Then, the plunger is broken to avoid the needle from being accidentally pushed outward and to avoid recycling of the needle and the barrel.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     (a) Technical Field of the Invention  
         [0002]     This invention relates to a retractable syringe, in particular to one which, after being used once, will enable the needle to retract into the barrel whereupon the plunger will be broken to prevent the needle and the barrel from being re-used.  
         [0003]     (b) Description of the Prior Art  
         [0004]     According to a World Health Organisation report, about 8 to 16 million of the world&#39;s population have contracted Hepatitis B, and about 2 to 4.5 million have contracted Hepatitis C, and about 70,000 to 150,000 people have contracted AIDS as a result of using dirty needles.  
         [0005]     A retractable syringe has the characteristic that the needle can be retracted into the barrel of the syringe to avoid oneself and other people from being accidentally hurt. Thus, the connection between the needle seat of the needle and the barrel has to have a pull resistance F, pressure resistance E, and reverse pull G, as shown in  FIG. 2 .  
         [0006]     If (a) pull resistance F (3 kg/cm) is large, there is a risk of dislocation of the needle onto the patient after it has been used. If (b) pressure resistance E (3 kg/cm) is large, the needle may be slid into the barrel before it is injected into the patient. If (c) reverse pull G is small, the needle can be pulled back to the barrel. Accordingly, it may not be possible to have a syringe with large pressure resistance E and a small reverse pull G  
         [0007]      FIG. 3  is a conventional back-pull type syringe having a needle seat A and a barrel B. Protrusion C and recess D are used for locking the needle seat and the barrel and the air tight seal of the barrel. This method solves the pull resistance F and pressure resistance E of the barrel, but the reverse pull G cannot be easily controlled. If there is a greater resistance between the needle seat and the barrel, the force needed for the needle seat to be pulled back to the barrel is greater. The larger the contact area, the larger the force exerted. This will be inconvenient for the user. If the resistance between the needle seat and the barrel is small, the reverse pull G is reduced but the air tight seal is poor. This may cause the needle to fall out onto the patient.  
         [0008]     Accordingly, it is an object of the present invention to provide a retractable type syringe which can mitigates the above drawback.  
       SUMMARY OF THE INVENTION  
       [0009]     It is an object of the present invention to provide a retractable syringe comprising a cap having a cylindrical shape with a circular rim seat at one end and the external surface of the cap being formed with anti-slip elongated slots and the interior of the cap having a stepped circular hole and a semi-circular protruded rim. The retractable syringe further includes a hub cover having a stepped cylindrical post and a hole at the center thereof A reinforcing rib is provided to the stepped cylindrical post and an arch-shaped circular bottom seat is provided to the lower end of the stepped cylindrical post. At the half position of the circular bottom seat is formed and the lower section of the bottom seat has a recessed rim which is firmly engaged with the protruded rim being formed. The lower section of the circular bottom seat has an arch-shaped protruded rim for firm engagement with the recessed rim at the hub bottom  
         [0010]     The inner circle of the circular bottom seat is provided with a guiding post and the lower section of the guiding post is formed as a protruded rim. The hub bottom extends the inwardly sloping bottom seat of the hub cover facilitating the engagement of the arch-shaped recessed rim and the protruded rim of the barrel. A cylindrical guiding holder is provided to the hub bottom which is mounted with the guiding post. A protruded rim is provided to the upper section of the inner circular of the guiding hole to control the distance of disengagement of the arch-shape recessed rim of the hub cover and the arch-shape protruded rim, and to fasten on the protruded rim of the hub cover facilitating the pulling of the hub cover back to the barrel. The inner section of the bottom seat has a conical hole and the upper section of the bottom seat is a recess which is in combination with the protruded rim of the hub cover and extends through the inwardly sloping bottom seat of the hub cover. The conical hole at the bottom seat is connected to a tapered circular hole. A barrel has a stepped cylindrical body having a hollow interior. The upper end of the inner opening is provided with a protruded rim for engagement with the recessed rim of the hub cover. The lower section of the inner hole is a protruded rim for engagement with the circular rim seat of the plunger to prevent the needle seat from being pushed outside of the barrel.  
         [0011]     The oval shaped handle of the syringe is an elongated protruded strap for preventing slipping. The plunger has a conical engaging hook and the center of the plunger has a V-shaped slot and the conical engaging hook for engagement with the inner engaging hook of the hub bottom so as to pull the hub cover and the hub bottom back to the barrel. The outside of the circular thin rim seat is engaged with the protruded rim of the barrel to prevent the needle seat from being pushed out of the barrel. The bottom of the thin circular seat is a wing flap having a sectioned area for breakage, and at the joining of one wing flap with another wing flap, a circular post is provided for breaking. One end of the plunger has a circular handle with elongated protruded strap for prevention of slipping and a gasket having a cylindrical shape with an interior having a center hole for connection with the circular rim seat of the plunger. The circular protruded rim is used for water stopping.  
         [0012]     The foregoing object and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts.  
         [0013]     Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a perspective exploded view of the syringe in accordance with the present invention.  
         [0015]      FIG. 1A  is a perspective view of the syringe in accordance with the present invention.  
         [0016]      FIG. 2  is a schematic view showing the application of the syringe in accordance with the present invention.  
         [0017]      FIG. 3  is a sectional view showing the conventional syringe.  
         [0018]      FIG. 4A  is a perspective view of the cap of the syringe in accordance with the present invention.  
         [0019]      FIG. 4B  is another perspective view of the cap of the syringe in accordance with the present invention.  
         [0020]      FIG. 4C  is a front view of the cap of the syringe in accordance with the present invention.  
         [0021]      FIG. 4D  is a sectional view of the cap of the syringe in accordance with the present invention.  
         [0022]      FIG. 4E  is an enlarged view of the bottom portion of the cap of the syringe in accordance with the present invention.  
         [0023]      FIG. 4F  shows a top view of the cap of the syringe in accordance with the present invention.  
         [0024]      FIG. 5A  is a perspective view of the hub cover of the syringe in accordance with the present invention.  
         [0025]      FIG. 5B  is a reverse perspective view of the hub cover of the syringe in accordance with the present invention.  
         [0026]      FIG. 5C  is a front view of the hub cover of the syringe in accordance with the present invention.  
         [0027]      FIG. 5D  is a sectional view of the hub cover of the syringe in accordance with the present invention.  
         [0028]      FIG. 5E  is a top view of the hub cover of the syringe in accordance with the present invention.  
         [0029]      FIG. 6A  is a perspective view of the hub bottom of the syringe in accordance with the present invention.  
         [0030]      FIG. 6B  is a reverse perspective view of the hub bottom of the syringe in accordance with the present invention.  
         [0031]      FIG. 6C  is a front view of the hub bottom of the syringe in accordance with the present invention.  
         [0032]      FIG. 6D  is a sectional view of the hub bottom of the syringe in accordance with the present invention.  
         [0033]      FIG. 6E  is a top view of the hub bottom of the syringe in accordance with the present invention.  
         [0034]      FIG. 7A  is a perspective view of the barrel of the syringe in accordance with the present invention.  
         [0035]      FIG. 7B  is a reverse perspective view of the barrel of the syringe in accordance with the present invention.  
         [0036]      FIG. 7C  is a front view of the barrel of the syringe in accordance with the present invention.  
         [0037]      FIG. 7D  is a sectional view of the barrel of the barrel of the syringe in accordance with the present invention.  
         [0038]      FIG. 7E  is an enlarged view of the top portion of the barrel of the syringe in accordance with the present invention.  
         [0039]      FIG. 7F  is a top view of the barrel of the syringe in accordance with the present invention.  
         [0040]      FIG. 8A  is a perspective view of the plunger of the syringe in accordance with the present invention.  
         [0041]      FIG. 8B  is a reverse perspective view of the plunger of the syringe in accordance with the present invention.  
         [0042]      FIG. 8C  is a front view of the plunger of the syringe in accordance with the present invention.  
         [0043]      FIG. 8D  is a top view of the plunger of the syringe in accordance with the present invention.  
         [0044]      FIG. 9A  is a perspective view of the gasket of the syringe in accordance with the present invention.  
         [0045]      FIG. 9B  is another perspective view of the gasket of the syringe in accordance with the present invention.  
         [0046]      FIG. 9C  is a front view of the gasket of the syringe in accordance with the present invention.  
         [0047]      FIG. 9D  is a sectional view of the gasket of the syringe in accordance with the present invention.  
         [0048]      FIG. 9E  is a top view of the gasket of the syringe in accordance with the present invention.  
         [0049]      FIG. 10  shows the injection step ( 1 ) in accordance with the present invention.  
         [0050]      FIGS. 11A, 11B  and  11 C are sectional views showing the injection step ( 2 ) in accordance with the present invention.  
         [0051]      FIGS. 11D, 11E  and  11 E are perspective views showing the injection step ( 2 ) in accordance with the present invention.  
         [0052]      FIGS. 12A , and  12 B are sectional views showing the injection step ( 3 ) in accordance with the present invention.  
         [0053]      FIG. 12C  is an enlarged view of the bottom portion of  FIG. 12A  in accordance with the present invention.  
         [0054]      FIGS. 12D and 12E  are perspective views showing the injection step ( 3 ) in accordance with the present invention.  
         [0055]      FIG. 13  is a sectional view showing the combination of the hub cover and the hub bottom in accordance with the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0056]     The following descriptions are of exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.  
         [0057]     Referring to  FIGS. 1, 1A ,  4 A,  4 B,  4 C,  4 D,  4 E,  4 F,  5 A,  5 B,  5 C,  5 D,  5 E,  6 A,  6 B,  6 C,  6 D,  6 E,  7 A,  7 B,  7 C,  7 D,  7 E,  7 F,  8 A,  8 B,  8 C,  8 D,  9 A,  9 B,  9 C,  9 D,  9 E, there is shown a retractable syringe comprising a cap  1  (shown in  FIGS. 4A, 4B ,  4 C,  4 D and  4 E) having a cylindrical shape with a circular rim seat  2  at one end and the external surface of the cap being formed with anti-slip elongated slots  3  and the interior of the cap  1  having a stepped circular hole  4  and semi-circular protruded rim  5  and  6  for securing the needle seat; a hub cover  7  ( FIGS. 5A, 5B ,  5 C and  5 D) having a stepped cylindrical post and a hole  8  for placing needle and needle adhesive at the center thereof, a reinforcing rib  9  provided to the stepped cylindrical post and an arch-shaped circular bottom seat  10  being provided to the lower end of the stepped cylindrical post and at the half position of the circular bottom seat inwardly sloping being formed and the lower section of the bottom seat a recessed rim  11  which is firmly engaged with the protruded rim  24  ( FIGS. 7, 7A ,  7 B,  7 C,  7 D,  7 E and  7 F) being formed, and the lower section of the circular bottom seat  10  having an arch-shaped protruded rim  12  for firm engagement with the recessed rim  20  ( FIGS. 6A, 6B ,  6 C,  6 D and  6 E) at the hub cover  7 , and the inner circle of the circular bottom seat  10  a guiding post  13  being provided and the lower section of the guiding post  13  being a protruded rim  14 ; the hub bottom  15  extending the inwardly sloping bottom seat of the hub cover  7  facilitating the engagement of the arch-shaped recessed rim  11  ( FIGS. 5A, 5B ,  5 C and  5 D) and the protruded rim  24  ( FIGS. 7A, 7B ,  7 C,  7 D,  7 E and  7 F) of the barrel  23  and a cylindrical guiding holder  16  being provided to the hub cover  7  which is mounted with the guiding post  1 , a protruded rim  24  ( FIGS. 7A, 7B ,  7 C,  7 D,  7 E and  7 F) being provided to the upper section of the inner circular of the guiding hole to control the distance of disengagement of the arch-shape recessed rim  11  of the hub cover  7  and the arch-shape protruded rim  24  ( FIGS. 7A, 7B ,  7 C,  7 D,  7 E and  7 F), and to fasten with the protruded rim  24  ( FIGS. 7A, 7B ,  7 C,  7 D,  7 E and  7 F) of the hub cover  7  facilitating the pulling of the hub cover  7 , back to the barrel, the inner section of the hub bottom  15 , having a conical hole  19  and the upper section of the bottom seat being a recess which is in combination with the protruded rim  12  (FIGS. SA,  5 B,  5 C,  5 D,  5 E) of the hub cover  7  and extends the inwardly sloping bottom seat of the hub cover  7 , the conical hole  19  at the bottom seat connected to a tapered circular hole  21 .  
         [0058]     The barrel  23  has a stepped cylindrical body ( FIGS. 7A, 7B ,  7 C,  7 D,  7 E and  7 F) having a hollow interior. The upper end of the inner opening is provided with a protruded rim  24  for engagement with the recessed rim  11  of the hub cover and the lower section of the inner hole being a protruded rim  7  for engagement with the circular rim seat  33  ( FIGS. 8A, 8B ,  8 C,  8 D) of the plunger  28  to avoid the needle seat from being pushed outside of the barrel  23  and the oval shaped handle  26  of the syringe being elongated protruded strap  27  for preventing slipping.  
         [0059]     The plunger  28  has a conic engaging hook  29  and the center of the plunger  28  is a V-shaped slot. The conic engaging hook  29  is for engagement with the inner engaging hook  22  ( FIGS. 6A, 6B ,  6 C,  6 D,  6 E) of the hub bottom  15  so as to pull the hub cover  7  and the hub bottom  15  back to the barrel  23 . The exterior of the circular thin rim seat  31  is engagement with the protruded rim  25  of the barrel  23  to prevent needle seat is pushed out of the barrel  23 , and the bottom of the thin circular seat is wing flap  34  having a sectioned area for breakage, at the joining of one wing flap  34  with another wing flap  34 . A circular post  36  is provided as breaking point  37 .  
         [0060]     One end of the plunger has a circular handle  38  with an elongated protruded strap  39  for preventing slipping. A gasket  40  has a cylindrical shape with an interior having a center hole for connection with the circular rim seat  31  of the plunger  28 , and the circular protruded rim  43  is used for water stopping.  
         [0061]     Referring to  FIG. 10 , this shows step  1  of the application of the syringe of the present invention, wherein the cap  1  is removed and medicine for injection is delivered into the barrel  23 . After the medicine has been fully delivered, the syringe is ready for injection.  
         [0062]      FIG. 11  shows step II application of the syringe. When injection of the medicine has been completed, the conical engaging hook  29  ( FIGS. 8A, 8B ,  8 C,  8 D) is in contact with the tapered circular hole  21  ( FIGS. 6A, 6B ,  6 C,  6 D,  6 E). The small end hole of the circular hole  21  engages with the engaging hook  29 . There is a resistance when the plunger  28  is pushed forward and it cannot enter the bottom needle seat  15 .  
         [0063]     Due to the V-shaped slot, when the plunger  28  moves forward, the engaging hook will retract inward and is engaged with the hub bottom  15 . When the engaging hook is in engagement, the engaging hook will restore to its original size. At this instance, the plunger  28  can be subjected to back pull movement.  
         [0064]     Due to the inward sloping of the circular bottom seat ( FIGS. 5A, 5B ,  5 C,  5 D,  5 E) of the hub cover, the outward extension is generated by the bottom needle seat  15  ( FIG. 13 ). There is a little resistance to the recessed rim  20  ( FIGS. 6A, 6B ,  6 C,  6 D,  6 E) of the protruded rim  12  ( FIG. 5A, 5B ,  5 C, and  5 D). When the plunger is retracted a little, the hub bottom  15  will be dislocated from the hub cover  7 . When the protruded rim  17  engages with the protruded rim  14 , the hub bottom  15  is dislocated fully with the hub cover  7 . At the same time, the bottom seat  10  of the hub cover  7  loses the stress produced by the hub bottom  15 , and the inward sloping shape is restored. The resistance between the protruded rim  24  ( FIGS. 7A, 7B ,  7 C,  7 D,  7 E and  7 F) with the barrel with the recess  11  is dislocated.  
         [0065]     In Step  3  (shown in  FIGS. 12A, 12B ,  12 C,  12 D,  12 E), as the hub cover  7  has dislocated fully with the barrel  23 , the needle seat can be easily pulled to the barrel. When the thin circular seat  33  ( FIGS. 8A, 8C ) engages at the protruded rim  25 , the plunger  28  cannot be pulled backward. At this instance, it will break at the breaking point  37  ( FIGS. 8A, 8C ), and the needle is contained within the barrel  23 .  
         [0066]     It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above.  
         [0067]     While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.