Abstract:
A fluid injecting/sampling apparatus is constructed to include a barrel, a needle holder holding a needle cannula, a plunger mounted with a rubber stopper and axially movably mounted in the barrel, and a rotary chuck coupled to the front end of the barrel and prohibited from a reversed rotation after having been turned relative to the barrel to unlock the needle holder for enabling the needle holder to be pulled backwards into the inside of the barrel by the plunger.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to medical implements and, more specifically, to a fluid injecting/sampling apparatus having improved barrel and rotary chuck.  
           [0003]    2. Description of the Related Art  
           [0004]    There is known a safety hypodermic syringe using a rotary chuck to control the engaging operation of pawls relative to the needle holder. The rotary chuck can be rotated relative to the barrel in reversed directions to lock or unlock the needle holder. Because the rotary chuck is reversible, this design cannot prohibit a reuse of the hypodermic syringe.  
           [0005]    Therefore, it is desirable to provide a fluid injecting/sampling apparatus that eliminates the aforesaid drawbacks.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a fluid injecting/sampling apparatus, which can easily operated to lock/unlock the needle holder. It is another object of the present invention to provide a fluid injecting/sampling apparatus, which prevents a reuse of the apparatus after its service.  
           [0007]    To achieve these and other objects of the present invention, the fluid injecting/sampling apparatus comprises a barrel, the barrel having a cylindrical body defining a longitudinally extended receiving hole, an elastically bendable spring strip and an extension portion forwardly extended from a front end of the cylindrical body, a pawl respectively formed on the spring strip at an inner side, an end stop formed on a front end of each the extension portion, a first locating hole and a second locating hole formed in the end stop, and a stop block backwardly axially extended from the end stop; a rotary chuck coupled to the extension portion of the barrel and rotatable relative to the barrel, the rotary chuck having a tubular body defining an axially extended through hole, an escape hole formed in the tubular body, an engagement block disposed inside the tubular body at a front end of the axially extended through hole and respectively engaged into the first locating hole of the barrel, a stop block respectively disposed adjacent to the engagement block and adapted to stop against the stop block of the barrel; and a needle holder, said needle holder having a holder body adapted to hold a needle cannula, and a locating groove extended around the periphery of the holder body and adapted to receive the pawl of the barrel for enabling the needle holder to be locked to the barrel. The rotary chuck is rotatable to move the engagement block over the end stop into engagement with the second locating hole, keeping the stop block stopped at the stop block of the barrel and the escape hole respectively aimed at the spring strip and the pawl. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is an exploded view of a fluid injecting/sampling apparatus having improved barrel and rotary chuck according to one embodiment of the present invention.  
         [0009]    [0009]FIG. 2 is an enlarged view of a part of FIG. 1, showing the structure of the front part of the barrel and the rotary chuck.  
         [0010]    [0010]FIG. 3 is an exploded plain view of the barrel and the rotary chuck for the fluid injecting/sampling apparatus according to the present invention.  
         [0011]    [0011]FIG. 4 is an end view of the rotary chuck for the fluid injecting/sampling apparatus according to the present invention.  
         [0012]    [0012]FIG. 5 is an assembly view of a part of the fluid injecting/sampling apparatus according to the present invention, showing the rotary chuck coupled to the barrel.  
         [0013]    [0013]FIG. 6 is a side view in section of the fluid injecting/sampling apparatus according to the present invention, showing the spring strips of the barrel stopped in shape.  
         [0014]    [0014]FIG. 7 is an end view of FIG. 6.  
         [0015]    [0015]FIG. 8 is a sectional view taken along line  8 - 8  of FIG. 6.  
         [0016]    [0016]FIG. 9 is similar to FIG. 6 but showing the deformable status of the spring strips.  
         [0017]    [0017]FIG. 10 is an end view of FIG. 9.  
         [0018]    [0018]FIG. 11 is a sectional view taken along line  11 - 11  of FIG. 9.  
         [0019]    [0019]FIG. 12 is a side view in section showing the plunger moved to the rear side of the barrel, the needle holder with the needle cannula received inside the barrel. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]    Referring to FIGS.  1 ˜ 4 , a fluid injecting/sampling apparatus having improved barrel and rotary chuck according to one embodiment of the present invention is shown used with a needle cannula  80 . The fluid injecting/sampling apparatus comprises a barrel  10 , a rotary chuck  20 , a needle holder  30 , a plunger  40 , and a rubber stopper  50 .  
         [0021]    The barrel  10  has a cylindrical body  11  defining a longitudinally extended receiving hole  12 , two elastically bendable opposing spring strips  13  and two opposing extension portions  15  forwardly extended from the front end of the cylindrical body  11 , two pawls  14  respectively formed on the free ends of the spring strips  13  and facing each other, an end stop  16  formed on the front ends of the extension portions  15 , two L-shaped first locating holes  17  and two L-shaped second locating holes  19  alternatively and equiangularly spaced around the periphery of the end stop  16 , and two opposing stop rods  18  backwardly axially extended from the end stop  18 .  
         [0022]    The rotary chuck  20  has a tubular body  21  defining an axially extended through hole  22 , two escape holes  23  formed in the peripheral wall of the tubular body  21  at two sides, two finger strips  24  bilaterally formed on the peripheral wall of the tubular body  21  at the rear end, a plurality of ribs  25  formed on the inside of the through hole  22 , two engagement blocks  27  bilaterally disposed in the front end of the through hole  22  and adapted to engage the first locating holes  17  of the barrel  10 , two stop blocks  28  respectively disposed adjacent to the inner side of the engagement blocks  27  and adapted to stop against the stop rods  18  of the barrel  10 .  
         [0023]    The needle holder  30  has a holder body  31  adapted to hold a needle cannula  80 , and a locating groove  34  extended around the periphery of the holder body  31  and adapted to receive the pawls  14  of the barrel  10 .  
         [0024]    The plunger  40  has an elongated plunger body  41 , a stopper retainer  42  disposed at the front end of the plunger body  41 , and a thumb rest  49  provided at the rear end of the plunger body  41  for the rest of the thumb.  
         [0025]    The rubber stopper  50  has a stopper body  51  fastened to the stopper retainer  42  and supported on the front end of the plunger body  41  and peripherally disposed in close contact with the inside wall (the peripheral wall of the receiving hole  12 ) of the inner barrel  10 .  
         [0026]    Referring to FIGS. 2 and 3, by means of the through hole  22 , the rotary chuck  20  is sleeved onto the end stop  16  of the barrel  10  for enabling the ribs  25  of the rotary chuck  20  to be stopped at the extension portions  15  of the barrel  10 . When sleeving the rotary chuck  20  onto the end stop  16  of the barrel  10 , the stop blocks  28  are forced to deform and to pass over the end stop  16 . When the stop blocks  28  moved over the end stop  16 , the rotary chuck  20  is prohibited from backward movement relative to the barrel  10 , i.e., the end stop  16  stops the rotary chuck  20  from falling out of the barrel  10 . When installed, the engagement blocks  27  are respectively received in the first locating holes  17 .  
         [0027]    FIGS.  5 ˜ 8  show the status of the fluid injecting/sampling apparatus before use where the needle holder  30  is locked. Before rotating the rotary chuck  20  relative to the barrel  10 , the tubular body  21  of the rotary chuck  20  is disposed around the spring strips  13  to hold the spring strips  13  in shape, i.e., the pawls  14  of the barrel  10  are held in engagement with the locating groove  34  of the needle holder  30 , and therefore the needle holder  30  is locked to the barrel  10  for normal operation.  
         [0028]    FIGS.  9 ˜ 11  show the needle holder  30  unlocking operation. When rotated the rotary chuck  20  relative to the barrel  10  through an angle to move the engagement blocks  27  over the end stop  16  of the barrel  10 , the escape holes  23  of the rotary chuck  20  are moved to the periphery of the spring strips  13  for enabling the spring strips  13  to be curved outwards, i.e., when pulling the plunger  40  backwards, the pawls  14  of the barrel  10  will be disengaged from the engagement blocks  27  for enabling the needle holder  30  to be pulled backwards with the plunger  40  to the inside of the barrel  10 .  
         [0029]    At this time, as shown in FIG. 10, the engagement blocks  27  are stopped by the end stop  16  of the barrel  10  to prohibit the rotary chuck  20  from reversed rotation, therefore the needle holder  30  cannot be locked to the barrel  10  for normal use again, i.e., the fluid injecting/sampling apparatus cannot be used again.  
         [0030]    [0030]FIG. 12 shows the needle holder  30  moved backwards with the plunger  40  and received inside the receiving hole  12  of the barrel  10 , keeping the needle cannula  80  out of touch of a person.  
         [0031]    As indicated above, the fluid injecting/sampling apparatus of the present invention has the following features:  
         [0032]    1. The rotary chuck and the barrel of the present invention can easily be assembled, and the rotary chuck can easily be operated to control engagement of the pawls with the needle holder.  
         [0033]    2. After rotary motion of the rotary chuck to unlock the needle holder from the barrel, the rotary chuck is prohibited from reversed rotation, and the pawls of the barrel cannot be forced into engagement with the needle holder again, prohibiting a reuse of the fluid injecting/sampling apparatus.