Abstract:
A tablet feeder that is simple in construction and yet capable of accurately preventing drawbacks from occurring due to jamming of medicine or the like. A motor ( 6 ) installed on a case support block ( 3 ) is driven to rotate a rotor ( 9 ) disposed in a medicine receiving case ( 1 ) through a plurality of gears. The tablets received in the medicine receiving case ( 1 ) are held in the pockets ( 10 ) of the rotor ( 9 ) and are moved to a discharge section ( 11 ) to discharge tablets therefrom. The gearing is composed of a driving gear ( 7 ) connected to the rotary shaft of the motor ( 6 ), and a driven gear ( 13 ) meshing with the driving gear ( 7 ). Installed in either of the power transmission paths extending from the motor ( 6 ) to the rotor ( 9 ) through the two gears ( 7, 13 ) is a power cut-off section ( 15, 17 ) that cuts off the power from the motor ( 6 ) when a force of a predetermined value or above acts on the rotor ( 9 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a medicine feeder. 
     2. Description of Related Art 
     Conventionally, there has been a medicine feeder comprising a case supporting base provided with a motor and a medicine containing case removably mounted on the case supporting base. In this kind of medicine feeder, when the motor is driven to rotate a rotor provided in the medicine containing case via a plurality of gears, the medicine held in pocket portions formed on the rotor can be discharged from a discharge portion of the case supporting base. 
     In the conventional construction, however, when a medicine is jammed and the rotation of the rotor is prevented, there is a risk that the medicine may be damaged or the motor may suffer burnout. 
     SUMMARY OF THE INVENTION 
     Thus, a problem of the present invention is to provide a medicine feeder that is simple in construction and yet capable of accurately preventing drawbacks from occurring due to jamming of the medicine or the like. 
     As a means for solving the aforementioned problem, the present invention provides a medicine feeder in which a motor provided in a case supporting base is driven to rotate a rotor in a medicine containing case supported in the case supporting base via a plurality of gears. Medicine contained in the medicine containing case are held in each pocket portion of the rotor and are moved to a discharge portion of the case supporting base to discharge the medicine from the discharge portion. 
     The plurality of gears are composed of a driving gear connected to a rotation shaft of the motor and a driven gear engaging with the driving gear. 
     Also, a power cut-off portion is provided in a power transmission passage reaching the rotor from the motor through the both gears so that power from the motor is cut off when a braking force of more than a predetermined value acts on the rotor. 
     According to the above construction, in a case where medicine such as tablets, capsules and so on is jammed and rotation of the rotor is prevented, the power cut-off portion does not allow a drive power from the motor to be transmitted to the rotor, and thereby any disadvantages such as damage to the medicine, burnout of the motor and so on would not occur. 
     It is preferable in that a desired effect can be obtained in spite of a simple construction in which the power cut-off portion comprises a friction generating member provided between the rotor and the driven gear. 
     It is preferable in that damage to the medicine, motor burnout, and so on can be reliably prevented considering properties of the medicine so that a friction force generated by the friction generating member is adjustable. 
     The friction generating member may comprise a ring member having an annular shape, and the ring member can be made of synthetic resin material. 
     The power cut-off portion may comprise indentations provided on either one of the rotor and the driven gear and protrusions provided on the other. The protrusions engage with the indentations such that the engagement of the indentations and the protrusions is released when a braking force of more than a predetermined value acts on the rotor. 
     According to the present invention, as the power cut-off portion is provided in the power transmission passage reaching the rotor from the motor, it is possible to reliably prevent any disadvantages such as damage to the medicine, burnout of the motor, and so on even if the medicine jam or so disables the motor from rotating. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front view of a tablet feed apparatus provided with a tablet feeder according to an embodiment of the present invention; 
         FIG. 2  is an exploded perspective view of the tablet feeder according to an embodiment of the present invention; 
         FIG. 3  is a bottom view of the tablet containing case shown in  FIG. 2 ; 
         FIG. 4  is a partly sectional view of a rotor of the tablet feeder shown in  FIG. 2 ; 
         FIG. 5  is a partly sectional view of a variation of the tablet feeder of  FIG. 4 ; 
         FIG. 6  is a partly sectional view of an another variation of the tablet feeder of  FIG. 4 ; 
         FIG. 7  is a partly sectional view of a rotor of the tablet feeder according to an another embodiment of the present invention; 
         FIG. 8  is a partly enlarged sectional view of the rotor of  FIG. 7 ; and 
         FIG. 9  is a partly sectional view of a variation of the tablet feeder of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, embodiments according to the present invention will be explained with reference to the accompanying drawings. 
       FIG. 1  shows a tablet feed apparatus  2  having a plurality of tablet feeders  1  according to the present invention. 
     In the tablet feed apparatus  2 , inner and outer double drums  22 ,  23  are contained inside a cabinet  21  with the upper and lower end rotatably supported. On the outer surface of each drum  22 ,  23  are provided the plurality of tablet feeders  1 , while on the inner surface are formed a plurality of drop guide passages  24  in which the tablets discharged from each tablet feeder  1  provided in a vertical direction drop. Beneath the drums  22 ,  23  are provided lower plates  25 ,  26  having shutters (not shown) for temporarily receiving the tablets dropping from each drop guide passage  24 . Under the lower plates  25 ,  26  are provided small hoppers  27  corresponding to each drop guide passage  24 . Each small hopper  27  receives the tablets dropping from the drop guide passages  24  of the inner drum  22  and the drop guide passages  24  of the outer drum  23 . Under the small hoppers  27  is provided a collection hopper  28  for collecting the tablets dropping from the small hoppers  27 . Beneath the collection hopper  28  is provided a packing hopper  29 . Under the packing hopper  29  is provided a tablet packing section  30 . 
     The tablet packing section  30  comprises a roll  33  comprising a wound packing sheet  31  that is removably mounted on a roll shaft  32 , a printer  34  for printing information such as patient name, tablet name, dosing time, dose and the like on the packing sheet  31  reeled out from the roll  33 , a triangle plate (not shown in detail) for folding the packing sheet  31  into two so that the tablets discharged from the packing hopper  29  can be introduced, a pair of heater rollers  35  for sealing the packing sheet  31  with the introduced tablets, and a conveyor  37  for conveying the medicine package belt  36 , which has passed through the heater rollers  35  and has been discharged in an oblique lower direction, in an oblique upper direction to direct it to a discharge port (not shown). 
     The tablet feeder  1 , as shown in  FIG. 2 , is constituted by a case supporting base  3  provided on the tablet feed apparatus  2  and a tablet containing case  4  removably mounted on the case supporting base  3 . 
     The case supporting base  3  is provided with guide portions  5  on the upper surface side by side with a predetermined distance. Inside the case supporting base  3  is housed a motor  6  which is driven and controlled based on a control signal from a control unit (not shown). The rotation shaft of the motor  6  protrudes from the upper surface of the case supporting base  3 . On the protruding portion is integrated a driving gear  7 . The case supporting base  3  is formed with a discharge passage  3   a  in which a sensor  14  is provided for detecting the tablets passing therethrough. 
     The tablet containing case  4  has a substantially box-like shape, the upper surface of which can be opened and closed by a lid  8 . The upper surface of the bottom wall of the tablet containing case  4  is formed in a substantially conical shape, in which a rotor  9  is provided. The upper surface of the rotor  9 , as shown in  FIG. 4 , has, a substantially conical shape and is formed with step portions  9   a  which gradually protrude at three equally spaced portions in a circumferential direction. On the outer surface of the rotor, pocket portions  10 , each of which has a groove shape extending in a vertical direction, are formed at a plurality of positions spaced with an equal angle. The pocket portion  10  has a width and depth that makes it possible to hold only one tablet contained in the case  4 . The bottom wall of the tablet containing case  4  is formed with a discharge port  11 . The discharge port  11  has a width dimension that permits the port to register with only one of the pocket portions  10  of the rotor  9 . The central portion of the bottom surface of the rotor  9  is provided a rotation shaft  12 . The rotation shaft  12  protrudes from the lower surface of the bottom wall of the tablet containing case  4 . On the outer periphery of the end surface of the rotation shaft  12  is formed an annular protruding portion  12   a.    
     A driven gear  13  is attached, by an attachment member  15 , to the rotation shaft of the rotor  9 . The attachment member  15  comprises a shaft portion  15   a  and a flange portion  15   b  and is fixed on the rotation shaft  12  of the rotor  9  with a screw  16  inserted into the central portion of the attachment member  15 . The shaft portion  15   a  is inserted into a central aperture  13   a  of the driven gear  13  to rotatably support the driven gear  13 . The flange portion  15   b  supports the driven gear  13  between the flange portion  15   b  and the end surface of the rotation shaft of the rotor  9  via a ring member  17 . The ring member  17  comprises, for example, an O-ring made of synthetic resin and generates a predetermined friction force in accordance with a gap between the rotor  9  and the attachment member  15 , i.e., a press contact force with the ring member  17 . A friction force is set so that when a tablet jam prevents the rotor  9  from rotating, a slip can be caused between the ring member  17  and the rotor  9  or the attachment member  15  before the tablet suffers damage such as a break or split. The driven gear  13  is made of synthetic resin material. On the upper surface of the driven gear  13  is formed an annular groove  13   b  with which the annular protruding portion  12   a , which is formed on the rotation shaft  12  of the rotor  9 , rotatably engages. On the lower opening edge portion is formed an annular recess portion  13   c  in which the ring member  17  is positioned. Annular grooves formed on the outer periphery of the upper and lower surfaces of the driven gear  13  are provided as a so called relief in order to make the thickness equal. 
     Operation of the tablet feeder  1  of the above construction will be explained hereinafter. 
     In accordance with a prescription data, the tablet feeder  1  containing the specified tablets is driven. That is to say, when the motor  6  is driven, drive power is transmitted to the driven gear  13  via the driving gear  7 . To the attachment member  15  from the driven gear  13 , the drive power is transmitted by a friction force against the ring member  17  positioned between the both members. Thus, rotation of the driving gear  7  allows the attachment member  15 , the driven gear  13  and the rotor  9  to rotate via the ring member  17  so that tablets held in the pocket portions  10  can be discharged from the discharge passage  3   a  one after another. The number of discharged tablets is counted by the sensor  14  provided in the discharge passage  3   a . When the discharged number reaches a predetermined number, the motor  6  is stopped. 
     For example, when a tablet jam prevents the rotor  9  from rotating and a braking force acts on the rotor  9 , a slip is caused between the attachment member  15  and the driven gear  13  so that a drive power of the motor  6  is cut-off. Therefore, no excessive load acts on the jammed tablet from the rotor  9  and the tablet does not suffer damage such as breakage or splitting. 
     The tablets discharged from each tablet feeder  1  fall on the lower plates  25 ,  26  through the drop guide passages  24 . When a shutter (not shown) is opened at a predetermined timing, the tablets are introduced into the tablet packing section  30  through the small hoppers  27 , the collection hopper  28  and the packing hopper  29 , and are then packed by one dose in the tablet packing section  30 . 
     In the aforementioned embodiment, the O-ring is used as the ring member  17  but the shape, material and so on of the ring member  17  is not limited to this. For example, as shown in  FIG. 5 , it is also possible to stick a ring-like rubber sheet  18  etc. on at least one of the contact surfaces between the driven gear  13  and the rotation shaft of the rotor  9  to change the friction coefficient. 
     Furthermore, in the aforementioned embodiment, the ring member  17  etc. is interposed between the rotor  9  (and the attachment member  1 ) and the driven gear  13  to cause a slip, though the same construction may be used between the rotation shaft of the motor  6  and the driving gear  7 . Also, instead of the driving gear  7  and the driven gear  13 , as shown in  FIG. 6 , rollers  7 ′,  13 ′ with rubbers  19 ,  20  attached on the outer surface thereof may be used so that the rubbers can come into contact with each other to cause a slip therebetween. 
     Furthermore, in the aforementioned embodiment, the attachment member  15  is attached by means of the screw  16 , though it is preferable in that the friction force against the ring member  17  be made adjustable forming a male screw on the outer end surface of the shaft portion  15   a  of the attachment member  15  and directly screw it into the rotor  9 . 
     In the aforementioned embodiment, as a power cut-off means of the present invention, a friction forming member such as the ring member  17 , the rubber sheet  18 , the rubbers  19 ,  20  and so on is used, though indentations may be provided on either one of the rotor  9  (or attachment member  15 ) and the driven gear  13  while protrusions that engage with the indentation may be provided on the other so that when a braking force of more than a predetermined value acts on the rotor  9 , engagements of the indentations and the protrusions are released and the drive power is cut-off. 
     For example, as shown in  FIG. 7 , indentations  41  are formed on the annular protruding portion  12   a  of the rotation shaft  12  of the rotor  9  while protrusions  42  which engage with the indentations  41  may be formed on the annular groove  13   b  of the driven gear  13 . A spring  43  may be provided between the annular recess portion  13   c  of the driven gear  13  and the flange portion  15   b  of the attachment member  15  to urge the driven gear  13  upward so that the engagement of the indentations  41  and the protrusions  42  can be maintained. The indentations  41 , as shown in  FIG. 8 , comprise a plurality of slopes  41   a  and step portions  41   b  which are continuously formed in a circumferential direction. In normal operation, the engagement of the indentations  41  and the protrusions  42  allows the drive power of the motor  6  to be transmitted to the rotor  9  from the driven gear  13 . When a tablet jam causes a braking force of more than a predetermined value to act on the rotor  9 , the protrusions  42  slide on the slopes of the indentations  41  and overpass the step portions  41   b  as the driven gear  13  moves downward, and thereby the drive power of the motor  6  can be cut-off. 
     Moreover, as shown in  FIG. 9 , indentations  41  may be formed on the annular recess portion  13   c  of the driven gear  13  while protrusions  42 , which engage with the indentations  41 , may be formed on the flange portion  15   b  of the attachment member  15 . In this case, as the engagements of the indentations  41  and the protrusions  42  are maintained by the weight of the driven gear  13 , the spring shown in  FIG. 7  is not necessary. 
     In the aforementioned embodiment, although the construction of discharging tablets as medicine has been described, other solid types of medicine such as capsules can be dealt with by the same construction.