Abstract:
A test tube cap removing apparatus includes a fixing unit that holds a test tube having an opening portion that is closed by a cap. A hold unit is situated above the cap in an axial direction of the test tube, has a position that is variable relative to the test tube in the axial direction, and is capable of contacting a top portion of the cap. A clamp unit is provided on the hold unit, supports the cap at side surfaces of the cap in a case where the hold unit is put in contact with the top portion of the cap, and removes the cap from the test tube in a case where the hold unit moves upwards relative to the test tube in the axial direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2003-306492, filed Aug. 29, 2003, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a test tube cap removing apparatus for automatically removing a cap that is attached to an opening portion of a test tube in which a specimen is to be contained. 
     2. Description of the Related Art 
     In a conventional test tube cap removing apparatus, a cap that closes the opening of a test tube is clamped by distal end portions of cap-removing arms in the state in which the test tube is clamped by a test tube clamper. In this apparatus, the cap-removing arms are pulled up by a cap-removing-arm drive cylinder, thereby automatically removing the cap. 
     Document 1 (Jpn. Pat. Appln. KOKAI Publication No. 5-228379) discloses a test tube cap removing apparatus wherein grippers are provided on the distal end portions of cap-removing arms. When the cap-removing arms are pulled up by a drive cylinder, the cap is rotated about its axis in association with inclining guides. 
     Test tubes, which are specimen containers, come in various sizes. For example, the relationship of “diameter×length” of the tube may be: φ13 mm×75 mm, φ13 mm×100 mm, φ16 mm×75 mm, or φ16 mm×100 mm. A specimen, such as blood, is contained in the test tube. 
     There are various types of caps for closing openings of test tubes, which include, for instance, a push-in type rubber cap, a cork cap, a screw cap, and a cap of a Sarstedt tube. 
     The test tube cap removing apparatus according to Document 1 is applicable to a case where a cap of a standard type, which is applied to a test tube of a fixed size, is to be removed. 
     However, with the test tube cap removing apparatus of Document 1, if the size of the test tube or the type of the cap is changed, it is difficult to remove the test tube cap. 
     In Document 1, the cap-removing arms of the test tube cap removing apparatus are provided with a mechanism for rotating the cap about its axis in association with the inclining guides when the cap is to be removed. 
     This rotating mechanism, however, is a mechanism that is designed mainly to reduce the force which is needed to remove the cap. This mechanism does not function to stably remove, e.g. a screw cap by rotating the screw cap with a necessary amount of rotation. 
     In short, Document 1 is silent on an adjusting mechanism for making the cap removing apparatus usable even when the size of the test tube or the type of the cap is changed. Such an adjusting mechanism is, for example, a mechanism for adjusting the positional relationship between a test tube clamper and a cap-removing arm, or a mechanism for removing a screw cap. 
     BRIEF SUMMARY OF THE INVENTION 
     According to an aspect of the present invention, there is provided a test tube cap removing apparatus comprising: a fixing unit that holds a test tube having an opening portion that is closed by a cap; a hold unit that is situated above the cap in an axial direction of the test tube, has a position that is variable relative to the test tube in the axial direction, and is capable of contacting a top portion of the cap; and a clamp unit that is provided on the hold unit, supports the cap at side surfaces of the cap in a case where the hold unit is put in contact with the top portion of the cap, and removes the cap from the test tube in a case where the hold unit moves upwards relative to the test tube in the axial direction. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a front view of an example of a test tube cap removing apparatus according to an embodiment of the present invention; 
         FIG. 2  is a front view of the example of the test tube cap removing apparatus in a state in which a drive unit reaches a lower limit position; 
         FIG. 3  is a front view of the example of the test tube cap removing apparatus at a time a cap removing operation is started; 
         FIG. 4  is a front view of the example of the test tube cap removing apparatus at a time the cap removing operation is completed; and 
         FIG. 5  is a front view of the example of the test tube cap removing apparatus in a state in which a clamp mechanism  50  is moved to a position above a cap discard duct. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of the present invention will now be described with reference to the accompanying drawings. 
     A test tube cap removing apparatus according to the embodiment, which is descried below, is capable of quickly and exactly removing a cap from a test tube even where test tubes of various sizes are used and various types of caps are attached to opening portions of test tubes. 
       FIG. 1  is a front view of an example of the test tube cap removing apparatus according to the embodiment of the present invention.  FIG. 1  shows a first operation state of the apparatus. 
     A convey mechanism  10 , which is provided below the test tube cap removing apparatus, conveys a test tube  1  with an opening closed by a cap  2 , to a predetermined position where a cap removing operation is to be performed. 
     The convey mechanism  10  conveys a holder  11 , which can hold the test tube  1  in a vertical state, to a predetermined position by means of a convey lane that comprises a guide rail  12  and a belt conveyor  13 . 
     A fixing mechanism  20  clamps the test tube  1  from both sides, which has been conveyed to the predetermined position by the convey mechanism  10 , and fixes the test tube  1 . 
     The fixing mechanism  20  comprises a plurality of pressure-contact rollers  25 ,  26 , piston/cylinder devices  21 ,  22 , and a rotary drive mechanism  29 . 
     The pressure-contact rollers  25  and  26  can clamp the test tube  1  from both sides. In this embodiment, two pressure-contact rollers  25  and  26  clamp the test tube  1 . Alternatively, three or more pressure-contact rollers may clamp the test tube  1 . 
     The piston/cylinder device  21 ,  22  advances/retreats the pressure-contact roller  25 ,  26 , thereby putting the pressure-contact roller  25 ,  26  in pressure contact with the outer peripheral surface of the test tube  1  with a predetermined pressure, or separating the pressure-contact roller  25 ,  26  from the outer peripheral surface of the test tube  1 . 
     The rotary drive mechanism  29  comprises a motor  27  and a deceleration mechanism  28 . 
     The motor  27  rotates at least one of the pressure-contact rollers  25  and  26 , thereby rotating the test tube  1  about its axis. In this embodiment, it is assumed that the motor  27  rotates the pressure-contact roller  25 . 
     The deceleration mechanism  28  decelerates the rotation by the motor  27 . 
     An elevation mechanism  30 , which is provided above the fixing mechanism  20 , vertically moves a drive unit, which is constructed by coupling slidable rings  31  and  32  using a coupling bar  33 , by means of a piston/cylinder device  34 . 
     A substantially middle part of the coupling bar  33  is connected to a driving end portion of a piston member  35  of the piston/cylinder device  34 . 
     A hold mechanism  40  comprises a pair of elevation shafts  41  and  42 , and a plate  47 , which has both end portions coupled to lower end portions of the elevation shafts  41  and  42  and is horizontally suspended. 
     The hold mechanism  40  is coupled such that the hold mechanism  40  is vertically slidable in a predetermined range, relative to the drive unit,  31  to  33 , of the elevation mechanism  30 . A lower end portion of the hold mechanism  40  is provided with a plate  47  that is able to contact a top portion of the cap  2  of test tube  1  by its own weight. 
     The paired elevation shafts  41  and  42  are vertically movably supported on a pair of bearings  43  and  44  that are attached to a support frame  62  of a support mechanism  60 . Nuts  45  and  46 , which serve as stoppers, are engaged with the paired elevation shafts  41  and  42  at some points along their lengths. The vertical positions of the nuts  45  and  46  are adjustable so that the nuts  45  and  46  may be positioned at the same level. 
     The slidable rings  31  and  32  of the elevation mechanism  30  are slidably fitted on the paired elevation shafts  41  and  42  at positions below the positions where the nuts  45  and  46  are engaged. 
     A contact portion  47   a , which comes in contact with the top portion of the cap  2  of test tube  1 , is provided at a central part of the lower surface of the plate  47  that is attached to the lower end portions of the elevation shafts  41  and  42 . 
     The contact portion  47   a  comes in contact with the top portion of the cap  2  of test tube  1  by its own weight. In this embodiment, the contact portion  47   a  is put in contact with the top portion of the cap  2  in the state in which the weight of the contact portion  47   a , plate  47 , elevation shafts  41  and  42 , etc. acts on the top portion of the cap  2 . 
     A clamp mechanism  50  is provided on the plate  47  of hold mechanism  40 . When the plate  47  contacts the top portion of the cap  2 , the clamp mechanism  50  clamps the cap  2  of test tube  1  from both sides. 
     In this embodiment, the clamp mechanism  50  comprises a pair of piston/cylinder devices  51  and  52 , which are disposed at both ends of the plate  47  of hold mechanism  40 , and clamp members  55  and  56 , which are attached to piston members  53  and  54  of the paired piston/cylinder devices  51  and  52 . 
     The clamp members  55  and  56  clamp the cap  2  of test tube  1  from both sides. 
     In this embodiment, in order to stably and surely clamp the cap  2 , a distal end portion of each clamp member  55 ,  56  is formed to have a pointed shape. 
     In the support mechanism  60 , the support frame  62 , which has a rectangular plate shape, moves in the horizontal direction (direction X) along a supporting guide rail  61  that is horizontally situated. The support frame  62  is driven by a drive shaft  63  and is movable between a position above the test tube  1  and a position above a cap discard duct unit for discarding the cap  2 . 
     In this embodiment, the test tube cap removing apparatus operates, for example, according to a sequence control of a central processing unit (CPU). 
     In the test tube cap removing apparatus according to the embodiment, the drive unit,  31  to  33 , of the elevation mechanism  30  lowers the hold mechanism  40 , brings the plate  47  into contact with the top portion of the cap  2 , and stops the lowering of the hold mechanism  40 . 
     As a result, the positions of the distal end portions of the clamp members  55  and  56  of the clamp mechanism  50 , which is disposed on the plate  47 , are set at such a level as to directly face lateral sides of the outer periphery of the cap  2 . 
     Subsequently, only the drive unit,  31  to  33 , of the elevation mechanism  30  continues to move downwards, and stops when the drive unit,  31  to  33 , reaches a lower limit position of the movable range. 
     If the clamp mechanism  50  operates, the clamp members  55  and  56  clamp the cap  2 . In the state in which the cap  2  is clamped by the clamp members  55  and  56 , the drive unit,  31  to  33 , of the elevation mechanisms  30  moves upwards. 
     Only the drive unit,  31  to  33 , of the elevation mechanism  30  is first raised. When the drive unit,  31  to  33 , abuts on the nuts  45  and  46  that serve as stoppers, the hold mechanism  40  is raised along with the drive unit,  31  to  33 . As a result, the cap  2  is removed from the test tube  1 . 
     In this embodiment, when the length size of the test tube varies, the level at which the plate  47  comes in contact with the top portion of the cap  2  will also vary in accordance with the variation in length of the test tube. 
     The test tube cap removing apparatus according to the present embodiment performs the same operation even if the length size of the test tube, which is to be set, is varied. Therefore, the test tube cap removing apparatus of this embodiment can properly remove the cap  2 , without being affected by the length of the test tube  1 . 
     In this embodiment, the clamp mechanism  50  includes the clamp members  55  and  56  with the pointed distal end portions that clamp the outer periphery of the cap  2 . The cap  2  is clamped in the state in which the pointed distal end portions of the clamp members  55  and  56  bite the outer periphery of the cap  2 . Thus, the cap  2  can stably and surely be clamped. 
     The fixing mechanism  20  of the test tube cap removing apparatus includes the rotary drive mechanism  29 , which rotates at least one of the pressure-contact rollers  25  and  26  that clamp the test tube  1  from both sides with a predetermined pressure, thereby rotating the test tube  1  about its axis. 
     By the rotary drive mechanism  29 , the test tube  1  can stably and continuously be rotated about its axis in a predetermined direction. As a result, even where the cap  2  attached to the test tube  1  is a screw cap, the cap  2  can stably and surely be removed. 
     Now referring to  FIG. 1  to  FIG. 5 , the operation of the test tube cap removing apparatus will now be described. 
     As is shown in  FIG. 1 , the test tube  1  is conveyed to the predetermined position by the convey mechanism  10 . The convey mechanism  10  has a stopping function. For example, the stopping function is realized in the following manner. A piston/cylinder device inserts a linear stopping pin, at a proper time, into a travel path along which the test tube holder  11  is conveyed over the convey lane. Thus, the test tube  1  is stopped at the predetermined position. 
     If the test tube  1  is stopped at the predetermined position, the test tube cap removing apparatus is set in a standby state for the cap removing operation. 
     The elevation mechanism  30  starts a lowering operation. With the lowering operation of the elevation mechanism  30 , the drive unit,  31  to  33 , move downwards. The hold mechanism  40 , which is suspended by the drive unit,  31  to  33 , also moves downwards. If the contact portion  47   a  of the plate  47  comes in contact with the top portion of the cap  2 , the hold mechanism  40  stops lowering at this position. When the contact portion  47   a  of plate  47  is in contact with the cap  2 , the weight of the plate  47 , as well as the weight of the elevation shafts  41  and  42 , etc., acts on the cap  2 . 
     Thus, in the case where the length size of the test tube  1  is relatively large and the position of the top portion of the cap  2  is high, the level at which the plate  47  stops is high. On the other hand, in the case where the length size of the test tube  1  is relatively small and the position of the top portion of the cap  2  is low, the level at which the plate  47  stops is low. 
     Regardless of the position where the plate  47  stops, the positions of the distal end portions of the clamp members  55  and  56  of the clamp mechanism  50 , which is disposed on the plate  47 , are set at such a level as to substantially directly face lateral sides of the outer periphery of the cap  2 . 
     Even after the lowering operation of the hold mechanism  40  is stopped, the elevation mechanism  30  continues the lowering operation. 
     The slidable rings  31  and  32  slide on the elevation shafts  41  and  42 , and the drive unit,  31  to  33 , continues the lowering operation. When the drive unit,  31  to  33 , reaches a lower limit position of the movable range, the drive unit,  31  to  33 , stops. 
       FIG. 2  is a front view of the example of the test tube cap removing apparatus in the state in which the drive unit,  31  to  33 , reaches the lower limit position. 
     In  FIG. 2 , height levels L1, L2 and LS indicate various levels of the lowered drive unit,  31  to  33 , of the elevation mechanism  30 . 
     Level L1 indicates the level of the drive unit,  31  to  33 , at the time when the contact portion  47   a  of the plate  47  comes in contact with the top portion of the cap  2  and the hold mechanism  40  stops lowering, in the case where the length size of the test tube  1  is relatively large and the level of the top portion of the cap  2  is high. 
     Level L2 indicates the level of the drive unit,  31  to  33 , at the time when the contact portion  47   a  of the plate  47  comes in contact with the top portion of the cap  2  and the hold mechanism  40  stops lowering, in the case where the length size of the test tube  1  is relatively small and the level of the top portion of the cap  2  is low. 
     Level LS indicates the level of the drive unit,  31  to  33 , in the case where the drive unit,  31  to  33 , continues the lowering operation even after the stop of lowering of the hold mechanism  40 , and finally the drive unit,  31  to  33 , stops. 
     When the contact portion  47   a  of the plate  47  comes in contact with the top portion of the cap  2 , the clamp mechanism  50  starts to operate. The clamp members  55  and  56  clamp the cap  2  from both sides. 
       FIG. 3  is a front view of the example of the test tube cap removing apparatus at a time the removing operation for removing the cap  2  is started. 
     In the state in which the cap  2  is clamped by the clamp members  55  and  56 , the elevation mechanism  30  starts to operate. With the operation of the elevation mechanism  30 , the drive unit,  31  to  33 , starts to move upwards. 
     Only the drive unit,  31  to  33 , moves upwards until the slidable rings  31  and  32  of the drive unit,  31  to  33 , abut on the nuts  45  and  46  of the hold mechanism  40 . 
     If the slidable rings  31  and  32  of the drive unit,  31  to  33 , abut on the nuts  45  and  46  of the hold mechanism  40 , the drive unit,  31  to  33 , starts pulling up the hold mechanism  40 . 
     Substantially at the same time as the hold mechanism  40  is pulled up, the motor  27  starts rotating in a predetermined direction. 
     With the rotation of the motor  27 , the pressure-contact roller  25  rotates in a predetermined direction. Consequently, the test tube  1  is rotated in a predetermined direction by the rotation of the pressure-contact roller  25 . 
       FIG. 4  is a front view of the example of the test tube cap removing apparatus at a time the removing operation for removing the cap  2  is completed. 
     With the pulling-up operation and the rotating operation combined, the operation for removing the cap  2  is smoothly started. The rotating operation is continuously performed for only a necessary time period by the rotary drive mechanism  29  that comprises the motor  27  and deceleration mechanism  28 . 
     Thus, whether the cap  2  is a push-in type cap or a screw cap, it can be removed. With this test tube cap removing apparatus, any type of cap can be removed very stably. 
       FIG. 5  is a front view of the example of the test tube cap removing apparatus in the state in which the clamp mechanism  50  is moved to a position above a cap discard duct. 
     If the removal of the cap  2  is completed, the operation of the support mechanism  60  is started. With the operation of the support mechanism  60 , the support frame  62  is pulled to the left (in  FIG. 4 ) by the drive shaft  63  and is moved along the support guide rail  61  to a position above a cap discard duct  70 . 
     In this state, the paired piston/cylinder devices  51  and  52 , which are attached to the plate  47  of the hold mechanism  40 , are rendered non-operative. 
     Since the paired piston/cylinder devices  51  and  52  are set in the non-operative state, the distal end portions of the clamp members  55  and  56  of clamp mechanism  50  are separated from the outer periphery of the cap  2 . As a result, the cap  2  is discarded in the cap discard duct  70  so that the cap  2  may be disposed of. 
       FIG. 5  shows the state immediately before the cap  2  is discarded in the cap discard duct  70 . 
     After the cap  2  is discarded, the support frame  62  moves back to a position above the convey mechanism  10  and fixing mechanism  20 . The test tube cap removing apparatus is thus restored to the initial state. Subsequently, the similar operations are to be repeated. 
     In the above-described embodiment, when the plate  47  of hold mechanism  40  comes in contact with the top portion of the cap  2  by its own weight, the clamp mechanism  50  clamps the cap  2 . 
     In addition, in the embodiment, the cap  2  is removed while the test tube  1  and cap  2  are rotated relative to each other. 
     Therefore, even where the size of the test tube varies, or even where the type of the cap varies, the cap can quickly and properly be removed from the test tube. 
     In this embodiment, test tubes  2 , from which caps  2  are removed, may successively be fed to a specimen analysis apparatus. 
     In the present embodiment, the piston/cylinder device is used as a drive actuator. Alternatively, an electromagnetic actuator, for instance, may be used as a drive actuator. 
     In the embodiment, the axis of the test tube  1  is set to be vertical. Alternatively, the axis of the test tube  1  may be set at an angle to the vertical direction. In this case, the piston/cylinder devices  21 ,  22 ,  51  and  52  may be configured to operate in a direction perpendicular to the axis of the test tube  1 . In addition, the elevation mechanism  30  and hold mechanism  40  may be configured to operate in the axial direction of the test tube  1 .