Abstract:
A sample suction apparatus including: a first member, a second member and a third member; a drive source; and a suction needle provided on the third member, wherein the drive source reduces a distance between the first member and the third member to perform: a first action of shifting the first member toward the third member to contact the first member with a portion of a specimen vessel; a second action of shifting the second member together with the third member toward the first member to contact the second member with another portion of the specimen vessel so that the specimen vessel is sandwiched between the first and second members; and a third action of shifting the third member toward the first member to bring the third member close to the second member so that the suction needle is inserted in the specimen vessel.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application is related to Japanese application No. 2000-205358 filed on Jul. 6, 2000, whose priority is claimed under 35 USC § 119, the disclosure of which is incorporated by reference in its entirety.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a sample suction apparatus. In particular it relates to a so-called piercing apparatus for piercing a plug-sealed specimen vessel with a suction needle (piercer) to suck up a sample.  
           [0004]    2. Description of Related Art  
           [0005]    To suck up a sample such as blood out of a sealed specimen vessel, commonly employed is a method of sucking up the sample by fixing the specimen vessel and then piercing a plug of the specimen vessel with a suction needle in the shape of an injection needle. Specifically, with respect to the specimen vessel tilted to have its plug lower than its bottom, a vessel supporting means is shifted to abut the bottom of the vessel and then a washing bath for washing the suction needle is shifted to abut the plug to fix the specimen vessel. Then the suction needle penetrates the washing bath and pierces the plug to suck up the sample contained in the vessel (see Japanese Examined Utility Model Publication No. HEI 7(1995)-3328).  
           [0006]    In a conventional apparatus as described above, two drive sources (air cylinders) are utilized to independently move the vessel supporting means, the washing bath and the suction needle. If the number of the drive source is reduced, size and production costs of the apparatus are reduced and the control thereof is simplified.  
         SUMMARY OF THE INVENTION  
         [0007]    Under such circumferences, the present invention has been achieved to provide an apparatus capable of surely fixing the specimen vessel by sandwiching it at both ends and piercing the plug with the suction needle, utilizing a single drive source.  
           [0008]    The present invention provides a sample suction apparatus comprising: a first member, a second member and a third member capable of linearly reciprocating along the same direction and spaced apart from each other, the second member being located between the first member and the third member; a drive source provided on the third member to enlarge and reduce a distance between the first member and the third member; an elastically compressible spacer inserted between the second member and the third member; and a suction needle provided on the third member, the suction needle pointing to the first member, wherein the drive source reduces the distance between the first member and the third member to perform: a first action of shifting the first member toward the third member to contact the first member with a portion of a specimen vessel; a second action of shifting the second member together with the third member toward the first member to contact the second member with another portion of the specimen vessel so that the specimen vessel is sandwiched between the first and second members; and a third action of shifting the third member toward the first member to compress the spacer to bring the third member close to the second member so that the suction needle is inserted in the specimen vessel.  
           [0009]    These and other objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a front view for illustrating an apparatus according to an embodiment of the present invention;  
         [0011]    [0011]FIG. 2 is a bottom view for illustrating the apparatus according to the embodiment of the present invention;  
         [0012]    [0012]FIG. 3 is a sectional view cut along a line A-A shown in FIG. 1;  
         [0013]    [0013]FIG. 4 is an enlarged sectional view illustrating a major part of FIG. 1;  
         [0014]    FIGS.  5 ( a ) to  5 ( d ) are views for illustrating an operation procedure of the apparatus according to the embodiment of the present invention; and  
         [0015]    [0015]FIG. 6 is a plan view for illustrating an arrangement of a hematology analyzer utilizing the sample suction apparatus shown in FIG. 1. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]    The first, second and third members according to the present invention may be sliders mounted on a linear rail. For example, commercially available RSR-ZM type sliders manufactured by THK Co., Ltd. may be utilized. In this case, a single rail, or two or three parallel rails may be used.  
         [0017]    It is suitable that the drive source according to the present invention reciprocates linearly. As such a drive source, may be used are a fluid pressure cylinder (e.g., an air cylinder and a hydraulic cylinder), an electric cylinder driven by a motor and the like.  
         [0018]    The elastically compressible spacer inserted between the second and third members may be, for example, a compressible spring.  
         [0019]    In the context of the present invention, the specimen vessel is a common vessel utilized for containing samples such as blood, urea and the like. It may be a tube-shaped vessel made of glass or plastic having a bottle and an aperture sealed with a rubber plug. For example, the specimen vessel contains blood as a specimen.  
         [0020]    The suction needle is preferably in the shape of an injection needle so that it pierces and penetrates the plug of the specimen vessel.  
         [0021]    To perform the first action according to the present invention, the first member is independently shifted to contact an end of the specimen vessel and then the second and third members are shifted after the first member has contacted the end.  
         [0022]    This is carried out by utilizing a stopper as the first member and a biasing member for biasing the third member toward a direction opposite to the first member. The biasing member may be a compressible spring.  
         [0023]    The second action according to the present invention is performed in such a manner that the third member pushes the second member toward the first member via the spacer after the first member has contacted the specimen vessel and stopped.  
         [0024]    The third action is performed in such a manner that the third member compresses the spacer after the second member has contacted the specimen vessel and stopped.  
         [0025]    According to the present invention, the second member may be provided with a washing bath for washing the suction needle so that the suction needle is washed before or after the insertion to the specimen vessel.  
         [0026]    The apparatus of the present invention may further comprise a sensor for detecting the completion of the second action. With the sensor, all the actions may be recovered from a state where the specimen vessel does not exist between the first and second members or a state where the specimen vessel is not properly introduced.  
         [0027]    Embodiment  
         [0028]    Hereinafter, the present invention will be detailed by way of an embodiment with reference to the drawings, but the invention is not limited thereto.  
         [0029]    [0029]FIG. 1 is a front view for illustrating a sample suction apparatus according to an embodiment of the present invention, FIG. 2 is a bottom view for illustrating the same and FIG. 3 is a sectional view cut along a line A-A shown in FIG. 1.  
         [0030]    As shown in these figures, a single rail  2  is fitted to a flap portion provided in a lower part of a substrate  1 . Sliders  3 ,  4  and  5  are slidably mounted on the rail  2 , which are capable of linearly reciprocating along the rail  2 , respectively. On the slider  5 , an air cylinder  7 , a suction needle (hereinafter referred to as a piercer)  8  and a spring supporting part  9  are mounted via a mounting part  6 .  
         [0031]    On the slider  4 , a washing bath  11  and a spring supporting part  12  are mounted via a mounting part  10 . On the slider  3 , a supporting part  14  is mounted via a mounting part  13 . The mounting part  13  is connected with a distal end of a piston rod  7   a  of the air cylinder  7  via a connection part  13   a.    
         [0032]    The piercer  8  is mounted on the mounting part  6  via a piercer supporting part  8   a . The supporting part  14  includes a conical hollow  14   a  to abut on a bottom  15   a  of a specimen vessel  15 . The specimen vessel  15  contains a liquid sample such as blood to be measured and is sealed with a rubber plug  15   b.    
         [0033]    The washing bath  11  is a hollow box having a drain  16  at the bottom thereof and small pores  17  and  18  through which the piercer  8  penetrates. Stoppers  19  and  20  are mounted on the substrate  1 . The stopper  19  restricts the movement of the air cylinder  7  along the direction of an arrow C shown in FIG. 1. The stopper  20  allows the piston rod  7   a  penetrate therethrough and restricts the movement of the connection part  13   a , i.e., the mounting part  13 , along the direction of the arrow C. A compressible spring  21  is wound about the piston rod  7   a  between the stopper  20  and the air cylinder  7  for biasing the air cylinder toward the direction of the arrow C.  
         [0034]    Further, as shown in FIG. 2, a compressible spring  22  is supported by spring supporting parts  9  and  12  and biases the spring supporting parts  9  and  12  to keep them apart from each other. An adjusting screw  23  (FIGS. 1 and 3) is provided on the mounting part  6  so that a tip of the adjusting screw  23  abuts on the mounting part  10  to adjust a positional relationship between a tip of the piercer  8  and the washing bath  11  (during washing of the piercer  8 ).  
         [0035]    The supporting part  14  is mounted on the mounting part  13  via a mounting plate  24  and biased toward the direction of the arrow C by a compressible spring  25  installed therein as shown in FIG. 4. Further, a photointerrupter  26  is mounted on the mounting plate  24 . The photointerrupter  26  is actuated by a tip  14   b  of the supporting part  14  when the supporting part  14  moves along the direction of an arrow B.  
         [0036]    The relationship in spring coefficient between the compressible springs  21 ,  22  and  25  is established as follows:  
         [0037]    Compressible spring  22 &gt;compressible spring  25   
         [0038]    Compressible spring  22 &gt;compressible spring  21   
         [0039]    An operation procedure of the thus constructed apparatus will be detailed with reference to FIGS.  5 ( a ) to  5 ( d ).  
         [0040]    As shown in FIG. 5( a ), a specimen vessel  15  held by a hand clipper (not shown) is introduced between the supporting part  14  and the washing bath  11  of the sample suction apparatus which is in a starting state.  
         [0041]    Then, the air cylinder  7  is actuated to drag the piston rod  7   a  along the direction of the arrow C. Since the compressible spring  21  is provided between the stopper  20  and the air cylinder  7  for biasing them to keep away from each other, the air cylinder  7  keeps contact with the stopper  19  without moving and the mounting part  13  is shifted along the direction of the arrow C to abut on the stopper  20  as shown in FIG. 5( b ). Thus, the supporting part  14  contacts the bottom  15   a  of the specimen vessel  15 .  
         [0042]    As the air cylinder  7  further drags the piston rod  7   a  along the direction of the arrow C, the compressible spring  21  is compressed since the distal end of the piston rod  7   a  is fixed with the stopper  20 , and then the air cylinder  7  and the mounting part  6  are shifted along the direction of the arrow B as shown in FIG. 5( c ).  
         [0043]    Simultaneously with the above, the mounting part  10  is shifted along the direction of the arrow B by force applied toward the arrow B via the compressible spring  22 . Accordingly, the washing bath  11  presses the rubber plug  15   b  of the specimen vessel  15  in the direction of the arrow B. Thus, the specimen vessel  15  is sandwiched between the supporting part  14  and the washing bath  11 , and at the same time, the supporting part  14  compresses the compressible spring  25  (FIG. 4) and the tip  14   b  thereof actuates the photointerrupter  26 .  
         [0044]    Then, as the air cylinder  7  further drags the piston rod  7   a  along the direction of the arrow C, the air cylinder  7  and the mounting part  6  are shifted toward the direction of the arrow B as shown in FIG. 5( d ). At this stage, the washing bath  11  is abutting on the specimen vessel  15  and does not move, so that the compressible spring  22  is compressed and the tip of the piercer  8  passes through the small pore  18  and penetrates the rubber plug  15   b  to enter the specimen vessel  15 .  
         [0045]    Then, as shown in FIG. 1, a suction apparatus  28  connected with the piercer  8  is actuated to suck up the sample from the specimen vessel  15  via the piercer  8 . A predetermined amount of the sucked sample is collected by a quantitative measurement part  27 .  
         [0046]    After the suction of the sample has been completed, the air cylinder  7  pushes out the piston rod toward the direction of the arrow B. As a result, the actions carried out in the order of FIGS.  5 ( a ) to  5 ( d ) are performed in an opposite order. When the sample suction apparatus returns to the state shown in FIG. 5( a ), washing solution is supplied from a washing apparatus  29  (FIG. 1) to the washing bath  11  via the piercer  8 .  
         [0047]    The washing solution is also supplied toward the piercer  8  from a cap (not shown) formed in the washing bath  11  so that the inner and outer walls of the piercer  8  are washed. Waste solution is then discharged from the drain  16 .  
         [0048]    Thus, the suction of the sample via the piercer  8  and the washing of the piercer  8  are performed.  
         [0049]    In the case where the photointerrupter  26  is not actuated while shifting from the state of FIG. 5( b ) to the state of FIG. 5( c ), a control section (not shown) judges that the specimen vessel  15  is absence or introduced improperly between the supporting part  14  and the washing bath  11 , and then returns the sample suction apparatus to the state of FIG. 5( a ).  
         [0050]    For easy suction of the sample from the specimen vessel  15  via the piercer  8 , it is preferable to incline the specimen vessel  15  by 30 to 45° with respect to a horizontal line so that the bottom  15   a  is held higher than the rubber plug  15   b . The inclination is carried out by adjusting the degree of angle of the substrate  1  with respect to the horizontal line. In this case, the rail  2  is also inclined and thus the air cylinder  7  is always biased toward the stopper  19  by its weight, so that the compressible spring  21  is omitted.  
         [0051]    [0051]FIG. 6 is a view for illustrating an arrangement of a hematology analyzer provided with the sample suction apparatus of the present invention.  
         [0052]    Racks  126  each have the shape of a test tube stand capable of carrying ten specimen vessels  15 .  
         [0053]    The racks  126  each carrying the specimen vessels  15  are arranged along a vertical line on a conveyer  112 . Then, all the racks  126  move toward a direction of an arrow D indicated in FIG. 6 and the rack  126  at the front is transferred to a conveyer  110  located on the left hand of the conveyer  112 .  
         [0054]    A hematology analyzer  118  is provided above the conveyer  110 . The rack  126  transferred on the conveyer  110  is stopped immediately below a stirrer  111  of the hematology analyzer  118 .  
         [0055]    After a specimen in one of the specimen vessels  15  at the front is stirred with the stirrer  111 , the rack  126  moves by a predetermined distance (an arrangement pitch among the specimen vessels  15  on the rack  126 ). The specimen vessel  15  immediately after subjected to stirring is held by a hand clipper  112  and withdrawn from the rack  126  to suck up the specimen (blood) by a suction apparatus  115 , and then returned to the rack  126 . The sucked specimen is quantified by a quantitative measurement part  113  and analyzed by an analysis part  114 . While the suction apparatus  115  sucks up the specimen from the front specimen vessel, the stirrer  111  stirs a specimen contained in the next specimen vessel  15 .  
         [0056]    Thus, the rack  126  moves intermittently by the arrangement pitch of the specimen vessels  15 . After the stirring and the suction of the specimen in the ten specimen vessels  15  (all the specimen vessels carried on the rack  126 ) are completed, the rack  126  is transferred along a direction of an arrow E. Then the specimen vessel  15  at the front of the following rack  126  is subjected to stirring. The racks  126  that went through the stirring and the suction of the specimen in the ten specimen vessels are finally collected at a rack collecting part  116  and arranged along a direction of an arrow F.  
         [0057]    In the hematology analyzer  118 , the sample suction apparatus shown in FIG. 1 is utilized as the suction apparatus  115 .  
         [0058]    According to the present invention, the action of fixing the specimen vessel and the action of inserting the suction needle in the specimen vessel are performed with a single drive source, so that the structure and the control of the sample suction apparatus are simplified.