Abstract:
The present invention relates to a simple and small cylinder pump, which can stably supply a medical fluid regardless of the installed height of a liquid container or a blood bag. The cylinder pump includes an upper casing, and a lower casing coupled to the upper casing. An upper rotation member is rotatably inserted in the upper casing. A lower rotation member slidingly contacting the upper rotation member is rotatably inserted in the lower casing. An inner wall of the upper casing, a lower outer surface of the upper rotation member, an inner wall of the lower casing, and an upper outer surface of the rotation member constitute a cylinder having a single-tube shape. Plungers are installed on the upper rotation member and on the lower rotation member, respectively, and rotate in the cylinder, the ends of which are closed.

Description:
[0001]    This application is a continuation of and claims priority to PCT Application No. PCT/KR2010/002152 filed on Apr. 8, 2010, and claims priority to Korean Patent Application No. 10-2010-0000924 filed Jan. 6, 2010. The entire disclosures of the PCT Application No. PCT/KR2010/002152 published as WO 2011/083892, and KR Application No. 10-2010-0000924 are hereby incorporated by reference in their entirety. 
     
    
     FIELD 
       [0002]    The present invention relates to a cylinder pump, and more specifically to a cylinder pump which is simple in structure and small in size, and allows the possibility of remote control regardless of the installation height of the receptacle or blood pack and the possibility of stable injection of a liquid medication or blood. 
       BACKGROUND 
       [0003]    It uses a syringe pump or infusion pump in order to inject a liquid medication or blood (hereinafter, ‘liquid medication or blood’ will be briefly described ‘liquid medication’) into the patient while controlling it at a constant and considerably high degree of precision. 
         [0004]    The conventional infusion pump has a high failure rate because overload is applied to the machine due to differences in elasticity of the tube by manufacturers. To get a high degree of precision for a syringe pump, the machine becomes complicated with a large size, and its use is possible only if it is installed immovably at a position. Although the syringe pump has a high degree of precision, it is hard to use it as a large volumetric pump, and using it as a large volumetric pump has an inconvenience that it has to be operated repetitively. 
         [0005]    In addition, the conventional syringe pump or infusion pump has the pressure of the discharged a liquid medication varied according to the installation position of the receptacle or blood pack, namely, the head of liquid. Therefore, there is inconvenience in that the receptacle or blood pack has to be installed at a certain height by using a pole. 
         [0006]    Also, since the degree of precision of the syringe pump or infusion pump is limited beforehand, a pump requiring a high degree of precision has the low feed rate of a liquid medication. Therefore, there is no way to use a syringe pump or infusion pump having different capacity according to the required injection rate and degree of precision of the liquid medication, so it becomes a burden to user that many syringe pumps or infusion pumps need to be provided beforehand. 
         [0007]    Moreover, the conventional infusion pump is of a type pressed or squeezed tube by the terminal of the machine, and the syringe pump is of a type that medicine is injected by pushing the plunger of syringe. Therefore, these pumps are all of a type of controlling medicine indirectly, so they may have the terminal overloaded or the machine structure is complicated; reliability is low because of frequent troubles, the price is high, nursing manpower is required, and remote control is difficult. 
       SUMMARY 
       [0008]    Accordingly, to solve the above problems, it is an object of the present invention to provide a cylinder pump which is simple in structure and small in size, allows for the possibility of stable injection of a liquid medication regardless of the installation height of the receptacle or blood pack, prevents overload of the machine, reduces required manpower by dint of remote control, and can use less accessory tubes, etc. that cause environmental pollution and are harmful to the human body. 
         [0009]    In order to accomplish the foregoing object, there is provided a cylinder pump comprising a cylindrical upper casing inside which an upper rotator is rotatably inserted; and a cylindrical lower casing which is engaged with the upper casing and inside which a lower rotator that is in rotation sliding contact with the upper rotator is rotatably inserted, the cylinder pump characterized in that: The inner wall of the upper casing and the lower outer circumference of the upper rotator, and the inner wall of the lower casing and the upper outer circumference of the rotator form a single tubular cylinder, the upper rotator and the lower rotator include plungers mounted thereon respectively, which make rotation in the tubular cylinder of whose ends are closed, the cylinder is provided with an inlet tube for a liquid medication to be flowed in and an outlet tube for the liquid medication to be flowed out, wherein the inlet and outlet tubes are protruded from the outer circumferences of the upper and the lower casings, the inlet tube and the outlet tube are placed in such a way that the central angle with respect to the center of rotation becomes more than one and less than two times the central angle (θ) of one plunger, and the upper rotator and the lower rotator are connected to a driving device to be able to rotate independently. 
         [0010]    In the present invention, the driving device includes a first driving unit which, with one plunger positioned between the inlet tube and the outlet tube, rotates with the other plunger in contact with one side of the one plungers to come into contact with the other side of one plunger, so as to position the one plunger between the inlet tube and the outlet tube while shifting the one plunger, and a second driving unit which, with the other plunger positioned between the inlet tube and the outlet tube, rotates with the one plunger in contact with one side of the other plunger to come into contact with the other plunger, so as to position the other plunger between the inlet tube and the outlet tube while shifting the other plunger, and the first driving unit and the second driving unit operate by taking turns. 
         [0011]    Namely, with one plunger between the inlet tube and the outlet tube stopped by a clutch stopper on the side of the first driving gear, the front of the other plunger is meshed with the gear of the first drive mechanism at the inlet tube position to be shifted in the normal direction where the one plunger is, pushing out into the inlet tube the liquid medication that is in the cylinder with a shape of about 300 degrees between the one plunger and the other plunger. Simultaneously with this, when the other plunger is shifted in the direction of the back of the one plunger, the back of the other plunger sucks the liquid medication from the inlet tube to fill it in the tubular pipe. 
         [0012]    If the other plunger agrees with the back of the one plunger and pushes the liquid medication completely out of the outlet tube and then agrees again with the one plunger, the first driving gear and the second driving gear are meshed simultaneously, so the one plunger and the other plunger that were between the inlet tube and the outlet tube are shifted simultaneously. When the one plunger is shifted toward the inlet tube, and the other plunger reaches between the inlet tube and the outlet tube, the clutch stopper that is on the side of the second driving gear controlling the other plunger fixes the other plunger. So the one plunger, while carrying out the other plunger&#39;s shifted action likewise, pushes the liquid medication out at the front and sucks it in at the back. 
         [0013]    Repeating the above action, the one plunger, the other plunger and the stopper provides precise control by the size of the tubular cylinder diameter and the control ratio of the driving device to feed a very small quantity or maximum quantity of a liquid medication. 
         [0014]    In addition, closers are inserted respectively between the upper casing and the upper rotator, between the lower casing and the lower rotator, between the upper rotator and the lower rotator and between the periphery of the upper casing and the periphery of the lower casing. 
         [0015]    Further, in the central portion of the upper casing is formed a through hole through which passes an outer driving gear of the driving device and an inner driving gear positioned in the hollow of the outer driving gear, and in the central portion of the upper rotator are concentrically formed in overlap an outer driving gear joint hole that is joinable with the outer driving gear and an inner driving gear through hole through which the inner driving gear can pass, and in the central portion of the lower rotator is formed an inner driving gear joint hole joinable with the inner driving gear. 
         [0016]    Further, the first driving unit and the second driving unit include position retainers installed thereon so as to suppress arbitrary rotation of the pair of the plungers. 
         [0017]    In addition, on the outer contour of the surface where the upper casing and the lower casing face each other are formed an upper contour closing seat and a lower contour closing seat respectively, and between the upper contour closing seat and the lower contour closing seat is sandwiched a contour closer. 
         [0018]    Further, any one of the upper contour closing seat and the lower contour closing seat is protruded toward the other one. 
         [0019]    Further, the flow rate of a liquid medication discharged through the outlet tube is determined by the cross sectional area of the cylinder and the rotation velocity of the plunger driven by the driving device. 
         [0020]    Preferably, the driving device includes a housing which forms a body and has a mounting portion on one side of which the cylinder pump is detachably mounted; a driving motor installed in a first bracket fixed on the inside of the housing; a main driving shaft which is rotatably fixed to the first bracket, and is connected to the output shaft of the driving motor to rotate, wherein the main driving shaft is provided with an inner motor-driven gear and an outer motor-driven gear mounted thereon; an inner driving shaft which is rotatably fixed to the a second bracket fixed on the inside of the housing, wherein the inner driving shaft is provided with an inner driven gear meshed with the inner motor-driven gear, and an inner driving gear formed at an end of the journal portion thereof to engage with the upper rotator; and an outer driving shaft which has a boss portion into which the journal portion of the inner driving shaft is inserted, and is rotatably fixed to a second bracket, wherein the outer driving shaft is provided with an outer driven gear mounted thereon corresponding to the inner motor-driven gear meshed with the outer motor-driven gear, and an outer driving gear formed at an end of the boss portion to engage with the lower rotator; and wherein the inner driving gear and the outer driving gear are exposed through the mounting portion; and the inner motor-driven gear and the outer motor-driven gear are identically formed gears, and have gear teeth formed only on a part of the respective outer circumference, wherein the inner motor-driven gear and the outer motor-driven gear are placed in such a way that they have a phase difference of 180° with respect to the main driving shaft. 
         [0021]    In addition, the inner motor-driven gear and the outer motor-driven gear have gear teeth formed only on a part of the respective outer circumference so that while rotating the inner driven gear and the outer driven gear (360−θ)°, the inner driven gear and the outer driven gear can be rotated (360−2Xθ)° only at a ½ rotation thereof. 
         [0022]    Preferably, the cylinder pump further comprises an inner position retainer and an outer position retainer which are installed in the second bracket for maintaining the position of the inner driven gear and the outer driven gear, in a state that the inner driven gear and the outer driven gear are not meshed with the inner motor-driven gear and the outer motor-driven gear, respectively. 
         [0023]    Further, each of the inner position retainer and the outer position retainer is provided with an inner boss seat and an outer boss seat having an M-shaped cross section for mounting an inner driven gear boss and an outer driven gear formed on the respective surfaces of the inner driven gear and the outer driven gear. 
         [0024]    The cylinder pump according to the present invention can feed a liquid medication at a considerably high degree of precision in spite of simple structure, and can cope with a large range of a liquid medication injection dosage per hour. 
         [0025]    In addition, the cylinder pump of the present invention is small in size, so it is easy to carry, and since it is not affected by the height of the receptacle or blood pack, it is possible to maintain the function of the pump without installing a receptacle or blood pack on a pole, so it can substitute the conventional various liquid medication dosage regulators. 
         [0026]    Therefore, the cylinder pump occupies a relatively small installation space, and even while a liquid medication is being injected by the cylinder pump, the patient can move freely. 
         [0027]    Also, since a liquid medication is controlled directly by the plunger in the cylinder pump, the flow rate per hour can be controlled precisely, so remote control by GPS is possible, and since it is possible to monitor the liquid medication feeding rate for the patient in real time, it is considerably helpful to a reduction of nursing manpower. 
         [0028]    Since the liquid medication driving device and operation unit are detachable, the operation unit can be made for disposable type products, so it is possible to feed a liquid medication more safely and sanitarily. 
         [0029]    Moreover, since the cylinder pump can be installed without using a pole, it can be installed in various places such as on the bed, floor and wheelchair; since the use of various accessory materials made of fossil fuel such as PVC tubes harmful to the human body and environment is reduced, carcinogenic substances generated during incineration of these products and environmental pollution can be reduced considerably. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0030]    The above objects, features and advantages of the present invention will become more apparent to those skilled in the related art in conjunction with the accompanying drawings. In the drawings: 
           [0031]      FIG. 1  is a perspective view of an infusion pump according to an embodiment of the present invention; 
           [0032]      FIG. 2  is a perspective view showing the driving unit in the driving device of the cylinder pump of  FIG. 1 ; 
           [0033]      FIG. 3  is a front view of the driving unit shown in  FIG. 2 ; 
           [0034]      FIG. 4  is a sectional view of the driving unit shown in  FIG. 2 ; 
           [0035]      FIG. 5  is a schematic view of the inner motor-driven gear and inner driven gear that rotate the inner driving gear in the driving unit of  FIG. 2 ; 
           [0036]      FIG. 6  is a schematic view of the outer motor-driven gear and outer driven gear that rotate the outer driving gear in the driving unit of  FIG. 2   
           [0037]      FIG. 7  is a schematic view showing by overlapping  FIG. 5  and  FIG. 6 . 
           [0038]      FIG. 8  is a left side view of an inner driving gear shaft with an inner driving gear formed thereon in the driving unit of  FIG. 2 ; 
           [0039]      FIG. 9  is a front view of the inner driving gear shaft shown in  FIG. 8   
           [0040]      FIG. 10  is a left side view of the outer driving gear shaft with the outer driving gear formed thereon in the driving unit of  FIG. 2 ; 
           [0041]      FIG. 11  is a front view of the outer driving gear shaft shown in  FIG. 10   
           [0042]      FIG. 12  is an exploded perspective view of the operating unit of the cylinder pump shown in  FIG. 1 ; 
           [0043]      FIG. 13  is a bottom view of the upper casing of the operating unit shown in  FIG. 12 ; 
           [0044]      FIG. 14  is a front sectional view of the upper casing shown in  FIG. 13 ; 
           [0045]      FIG. 15  is a plan view of the upper rotator in the operating unit shown in  FIG. 12 ; 
           [0046]      FIG. 16  is a bottom view of the upper rotator shown in  FIG. 15   
           [0047]      FIG. 17  is a plan view of the lower rotator in the operating unit of  FIG. 12 ; 
           [0048]      FIG. 18  is a bottom view of the lower rotator of  FIG. 17 ; 
           [0049]      FIG. 19  is a front view of the plunger in the operating unit of  FIG. 12 ; 
           [0050]      FIG. 20  is a plan view of the lower casing in the operating unit of  FIG. 12 ; 
           [0051]      FIG. 21  is a front sectional view of the lower casing shown in  FIG. 20 ; and 
           [0052]      FIG. 22  is a view schematically showing the operating sequence of the operating unit after assembling the operating unit of  FIG. 12 . 
       
    
    
     DESCRIPTION OF REFERENCE NUMERALS IN DRAWINGS 
       [0000]    
       
         
           
               100 : Driving device,  102 : Housing 
               104 : Mounting portion,  106 : Operation unit 
               108 : Driving motor,  110 : First bracket 
               111 : First support,  112 : Output shaft 
               114 : Main driving gear,  116 : Main reduction gear 
               118 : Main driving shaft,  120 : First bearing 
               122 : Second bracket,  124 : Inner motor-driven gear 
               126 : Inner driven gear,  127 : Inner driven gear boss 
               128 : Outer motor-driven gear,  129 : Third bearing 
               130 : Outer driven gear,  131 : Outer driven gear boss 
               132 : Second bearing,  133 : Inner outer position retainer 
               134 : Fourth bearing,  135 : Inner boss seat 
               136 : Fifth bearing,  137 : Outer position retainer 
               138 : Sixth bearing,  139 : Outer boss seat 
               140 : Second support,  142 : Third bracket 
               143 : Enlarged diameter portion,  144 : Inner driving shaft 
               145 : Journal portion,  146 : Inner driving gear 
               148 : Outer driving shaft 
               150 : Outer driving gear,  200 : Operating unit 
               202 : Upper casing,  203 : Upper contour closing seat 
               204 : Upper casing body,  205 : Upper joint boss 
               206 : Through hole,  208 : Upper closing seat 
               210 : Upper rotator slot,  212 : Upper cylinder 
               214 : Inlet tube,  216 ,  276 : Outlet tube 
               218 : Upper closer,  220 : Upper rotator 
               222 : Upper rotator body,  224 : Upper top side closing slot 
               226 : Outer driving gear joint hole 
               228 : Inner driving gear through hole 
               230 : Upper pusher,  232 ,  234 : Upper insert boss 
               236 ,  238 : Upper bottom side closing boss 
               240 : Upper bottom side closing slot 
               242 : Intermediate closer,  244 : Lower rotator 
               246 : Lower rotator body 
               248 ,  250 : Lower top side closing boss 
               252 : Lower top side closing slot 
               254 : Inner driving gear joint slot 
               256 : Lower pusher,  258 ,  260 : Lower insert boss 
               262 : Lower bottom side closing slot,  263 : Lower closer 
               264 : Lower casing,  266 : Lower closing seat 
               268 : Lower rotator slot,  270 : Lower cylinder 
               272 : Lower casing body,  274 : Lower contour closing seat 
               276 : Lower joint boss,  278 ,  280 : Plunger 
               282 ,  284 : O-ring,  286 : Plunger body 
               288 : Insert slot,  290 ,  292 : Insert slot 
               294 : Outer contour closer 
           
         
       
     
       DETAILED DESCRIPTION 
       [0098]    The present invention will now be described more fully hereinafter with reference to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views. In the embodiments of the present invention, detailed description of the publicly known functions and configurations that are judged to be able to make the purport of the present invention unnecessarily obscure are omitted. 
         [0099]    The cylinder pump according to the present invention does not use a conventional method of squeezing the tube or regulating the flow rate by pushing the plunger, but uses a method of carrying out the inflow and outflow of a liquid medication simultaneously as the two impellers in the tubular cylinder are rotated alternately one by one, namely the principle of the method controlling the flow rate directly. 
         [0100]    Accordingly, the method used in the present invention can regulate the flow rate from minute to large by the size and rotation velocity of the cylinder and impeller. 
         [0101]    Therefore, the core of the present invention is to regulate the minute flow rate accurately by minute displacement of the impeller at the operation unit. 
         [0102]    In particular, the cylinder pump according to the present invention is composed of a driving device and an operation unit detachably mounted to the driving device. Accordingly, the driving device can be used permanently, and the operation unit can be used disposably. 
         [0103]      FIG. 1  is a perspective view of the cylinder pump according to an embodiment of the present invention. The cylinder pump consists of a driving device  100  and an operation unit  200 . As mentioned above, the operation unit  200  is detachably assembled to the driving device  100  for disposable type products. 
         [0104]    The driving device  100  includes a first driving unit, which with the one plunger, positioned between the inflow pipe and the outflow pipe, rotates with the other plunger in contact with one side of the one plunger and positions the one plunger between the inflow pipe and the outflow pipe while shifting the one plunger in contact with the other side of the one plunger, and a second driving unit, which with the other plunger positioned between the inflow pipe and the outflow pipe, rotates with the one plunger in contact with one side of the other plunger and positions the other plunger between the inflow pipe and the outflow pipe while shifting the other plunger in contact with the other side of the other plunger, and the first driving unit and the second driving unit operate by taking turns. 
         [0105]    Accordingly, the driving device  100  is provided with a housing  102 , and a mounting portion  104  on one side of the housing  102  for mounting the operating unit  200 , and in the mounting portion  104  are placed an inner driving gear  146  and an outer driving gear  150  of the driving unit to be described later. 
         [0106]    On one side the housing  102  is placed an operation unit  106  for operating the operating unit  200  as you please. 
         [0107]      FIG. 2  is a perspective view of the driving unit contained in the driving device  100  of the cylinder pump, and  FIG. 3  is a front view of the driving unit, and  FIG. 4  is a sectional view of the driving unit. 
         [0108]    The driving means of the driving unit is a driving motor  108 , which drives the inner driving gear  146  and the outer driving gear  150  respectively through a plurality of gear trains. 
         [0109]    The driving motor  108  is fixed to the first bracket  110 , and at one end of the output shaft  112  of the driving motor  108  is monolithically installed a main driving gear  114 . The main driving gear  114  is meshed with a main reduction gear  116  to increase the torque ratio. Namely, the main reduction  116  has more teeth than the main driving gear  114 , so it increases the torque through rotational reduction. Due to this, the load applied to the driving motor  108  can be reduced, and the selection range of the driving motor  108  according to capacity broadens. 
         [0110]    The main reduction gear  116  is monolithically installed at one end of the main driving shaft  118 . As shown in  FIG. 3 , opposed end portions of the main driving shaft  118  are rotatably mounted to the a first bracket  110  and a second bracket  122  through a first bearing  120  and a second bearing  132 , respectively. 
         [0111]    The first bracket  110  and the second bracket  122  are fixed on the housing  102 . And in order to support the first bracket  110  and the second bracket  122  and fix them to the housing  102 , a first support  111  and a second support  140  may be additionally provided. 
         [0112]    And on the outer circumference of the main driving shaft  118  are monolithically fixed the inner motor-driven gear  124  and the outer motor-driven gear  128 . Accordingly, the rotation velocity in the inner electrical gear  124  and the outer motor-driven gear  128  are equal. 
         [0113]    The inner motor-driven gear  124  is meshed with the inner driven gear  126  as shown in  FIG. 5 , and the outer motor-driven gear  128  is meshed with the outer driven gear  130  as shown in  FIG. 6 . 
         [0114]    The inner motor-driven gear  124  and the outer motor-driven gear  128  are the same gears, but when fixed on the main driving shaft  118 , and when projected as shown in  FIG. 7  based on the main driving shaft  118 , they are installed in mutually symmetrical positions. 
         [0115]    First will be described the relation between the inner motor-driven gear  124  and the inner driven gear  126 . As shown in  FIG. 5 , the inner motor-driven gear  124  has only 22 teeth formed on the circumference on which 40 teeth can be seated, and the area of angle α, which is the remaining portion, has no teeth. Accordingly, only 22 teeth of the inner motor-driven gear  124  are meshed with the inner driven gear  126  and rotate the inner driven gear  126 . 
         [0116]    The inner driven gear  126  has 24 teeth formed on the circumference thereof. Accordingly, the central angle occupied by one tooth is 15°, and while the inner motor-driven gear  124  makes one rotation the inner driven gear  126  can rotate 330°. Namely, while the inner motor-driven gear makes one rotation, the inner driven gear  126  rotates by 30° less, which is the central angle occupied by two teeth. At this time, the 30° angle of rotation that the inner driven gear  126  lacks is equal to the central angle occupied by plungers  278  and  280  to be described later. Accordingly, as the central angle occupied by the plungers  278  and  280  decreases, the angle of rotation of the inner driven gear  126  per rotation of the inner motor-driven gear  124  increases. 
         [0117]    After all, the diameter and the number of teeth of the inner motor-driven gear  124  and the diameter and the number of teeth of the inner driven gear  126  are sufficient if they can rotate the inner driven gear  126  during one rotation of the inner motor-driven gear  124  as much as the size resulting from subtracting from 360° the central angle occupied by plungers  278  and  280 , and if necessary, more gears may be used. 
         [0118]    Next will be explained the relation between the outer motor-driven gear  128  and the outer driven gear  130 . As shown in  FIG. 6 , the outer motor-driven gear  128  has only 22 teeth formed on the circumference that can have 40 teeth seated thereon, and there are no teeth in the area of angle β, which is the remaining portion. Accordingly, only 22 teeth of the outer motor-driven gear  128  are meshed with the outer driven gear  130  to rotate the outer driven gear  130 . 
         [0119]    The outer driven gear  130  has 24 teeth formed on the circumference thereof. Accordingly, the central angle occupied by one tooth is 15°, and while the outer motor-driven gear  128  makes one rotation, the outer driven gear  130  can rotate 330°. Namely, while the outer motor-driven gear makes one rotation, the outer driven gear  130  rotates by 30° less, which is the central angle occupied by two teeth. At this time, the 30° angle of rotation that the outer driven gear  130  lacks is equal to the central angle occupied by plungers and  278  and  280  to be described later. Accordingly, according as the central angle occupied by plungers  278  and  280  decreases, the angle of rotation of the outer driven gear  130  per rotation of the outer motor-driven gear  128  increases. 
         [0120]    After all, the diameter and the number of teeth of the outer motor-driven gear  128  and the diameter and the number of teeth of the outer driven gear  130  are sufficient if they can rotate the inner driven gear  130  during one rotation of the inner motor-driven gear  128  as much as the size resulting from subtracting from 360° the central angle occupied by plungers  278  and  280 , and if necessary, more gears may be used. 
         [0121]    And the inner driven gear  126  and the outer driven gear  130  rotate independently without affecting each other. For this, the inner driven gear  126  is installed on the inner driving shaft  144 , and on the outer driven gear  130  is formed a boss portion  152  into which the journal portion  145  of the inner driving shaft  144  is inserted. As a result, the outer driven gear  130  can rotate independently of the inner driven gear  126  due to the sliding rotation of the boss portion  152  and the journal portion  145 . 
         [0122]    The inner driving shaft  144  is rotatably mounted on the first bracket  110  through a third bearing  129  and one side of a third bracket  142  through a fourth bearing  134 . The outer driving shaft  148  is rotatably mounted on the other side of the third bracket  142  through a fifth bearing  136  and on the second bracket  122  through a sixth bearing  138 . The third bracket  142  is fixed on the housing  102 . 
         [0123]    In addition, at one end of the right side of the inner driving shaft  144  is formed the inner driving gear  146 , and on one end of the right side of the outer driving shaft  148  is formed the outer driving gear  150 , and as shown in  FIG. 2  and  FIG. 3 , the inner driving gear  146  is installed so as to be protruded to the right side more than the end portion of the outer driving gear  150 . 
         [0124]    In the embodiment of the present invention, both the outer driving gear  150  and the inner driving gear  146  are formed in a cross shape, but the shape of the outer driving gear  150  and the inner driving gear  146  are not particularly limited thereto. 
         [0125]    And on the third bracket  142  are installed the inner and outer position retainers  133  and  137  that can prevent arbitrary rotation of the inner driving gear  146  and the outer driving gear  150 . 
         [0126]    In the inner and outer position retainers  133  and  137  are formed an inner boss seat  135  and an outer boss seat  139  to match an inner driven gear boss  127  and an outer driven gear boss  131  formed respectively on the surfaces (upper surfaces or lower surfaces) of the inner driven gear  126  and outer driven gear  130 , as shown in  FIGS. 5 and 6 . 
         [0127]    The inner driven gear boss  127  and the outer driven gear boss  131  have protruded structures in a shape of a bar whose radial outside end portion is rounded, and the inner boss seat  135  and the outer boss seat  139  are formed roughly in an M shape for the inner and outer driven gear bosses  127  and  132  to be mounted. The M shapes of the inner and outer driven gear bosses  127  and  132  are also rounded, so that the inner driven gear boss  127  and the outer driven gear boss  131  are formed detachably from the inner and outer driven gear bosses  127  and  132  in case external force is applied. 
         [0128]    The driving device  100  is composed basically as mentioned above. Next, the output form of the driving device  100 , namely, the operating mode of the outer driving gear  150  and the inner driving gear  146  according to the rotation of the driving motor  108 , will be described. 
         [0129]    Rotation of the driving motor  108  is transmitted to the main reduction gear  116  via the main driving gear  114  to cause speed reduction and torque increase. And the main driving shaft  118  is rotated by rotation of the main reduction gear  116 , and the inner motor-driven gear  124  and the outer motor-driven gear  128  rotate at an angular velocity the same as the main driving shaft and in the same direction. 
         [0130]    At this time, suppose the state of  FIG. 7  is an initial state, then while the main driving shaft  118  makes a ½ rotation clockwise, the outer motor-driven gear  128  rotates the outer driven gear  130  by 300° (that is, as much as 20 teeth). And the inner motor-driven gear  126  rotates the inner driven gear  126  by 30° (that is, as much as two teeth) only at the time of starting; after that it does not rotate the inner driven gear  126 . 
         [0131]    Next, while the main driving shaft  118  makes an additional ½ rotation clockwise in this state, the inner motor-driven gear  124  rotates the inner driven gear  126  by 300° (that is, as much as 20 teeth). And the outer motor-driven gear  128  rotates the outer driven gear  130  by 30° (that is, as much as two teeth) only at the initial state; after that it does not rotate the outer driven gear  130 . 
         [0132]    Namely, while the inner driven gear  128  and the outer driven gear  130  rotate 300° respectively, only either one rotates, but in the area γ that is oblique-lined in  FIG. 7  (that is, the area as much as two teeth, 30°), they rotate simultaneously. 
         [0133]    Accordingly, the inner driven gear  126  and the outer driven gear  130  carry out the next actions repetitively by the rotation of the driving motor  108 :
       1) The inner driven gear  126  only rotates 300°;   2) The inner driven gear  126  and the outer driven gear  130  rotate 30° simultaneously;   3) The outer driven gear  130  only rotates 300°; and   4) The inner driven gear  126  and the outer driven gear  130  rotate 30° simultaneously.       
 
         [0138]    Accordingly, the inner driven gear  126 , the inner driving gear  146  formed monolithically with the outer driven gear  130  by the outer driving shaft, and the outer driving gear  150  respectively rotate independently. 
         [0139]    However, in the process that the inner driving gear  146  and the outer driving gear  150  respectively rotate plungers  278  and  280  to be described later, negative pressure or positive pressure acts between a pair of the plungers  278  and  280 . Therefore, it is preferable to additionally install the position retainers  133  and  137  as mentioned above on the outer driving shaft  148  and the inner driving shaft  144  on which the inner driving gear  146  and the outer driving gear  150  are installed, so that the angle positions of the plungers  278  and  280  are not varied by the negative pressure and positive pressure between the pair of the plungers  278  and  280 . 
         [0140]    Accordingly, unintended variation of angle positions of the plungers  278  and  280  due to the position retainers  133  and  137  do not occur, and it is possible to suppress the backlash between the inner motor-driven gear  124  and the inner driven gear  126  where engagement and separation of the gear teeth occur repeatedly and between the outer motor-driven gear  128  and the outer driven gear  130 . 
         [0141]    Next, the operating unit  200  detachably mounted to the driving device  100  of cylinder pump will be described. The operating unit  200  is operated by the rotation of the inner driving gear  146  and the outer driving gear  150  of the driving device  100 . Here, the rotation of the inner driving gear  146  and the outer driving gear  150  can be operated by the above-mentioned driving device  100 , but as long as the above-mentioned motion characteristics are satisfied, the composition of the driving device  100  is not particularly limited. 
         [0142]    The operating unit  100  basically includes an upper casing  202  and a lower casing  264  that make the body, an upper rotator  222  inserted into the upper casing  202 , and a lower rotator  244  inserted into the lower casing  264 . 
         [0143]    In the upper casing  202  are formed an inlet tube  214  for a liquid medication to be introduced into the operating unit  100  and an outlet tube  216  for feeding a liquid medication to the liquid medication tube, etc. The inlet tube  214  and the outlet tube  216  are formed in the lower casing  264 , or they can be formed half and half in the upper casing  202  and the lower casing  264 , respectively. 
         [0144]    And in the upper casing  202  and the lower casing  264  are formed an upper cylinder  212  and a lower cylinder  270  respectively, and a cylinder in the shape of one tube is made by the upper casing  202 , the lower casing  264 , and the outer circumferences of the upper rotator  220  and the lower rotator  244 . And in the cylinder are formed the inlet tube  214  and the outlet tube  216  in such a way that they communicate with each other. 
         [0145]    The inlet tube  214  and the outlet tube  216  are deviated as much as ½ of the thickness with respect the center of the upper casing  202  and the lower casing  264 , as shown in  FIG. 13  and  FIG. 20 . And the angle between the inlet tube  214  and the outlet tube  216  is 30°. This agrees with the central angle 30° occupied by plungers  278  and  280  to be described later, and the purpose of this is not to close the inlet tube  214  and the outlet tube  216  when either of the plungers  278  and  280  is positioned between the inlet tube  214  and the outlet tube  216 . 
         [0146]    The upper casing  202  includes, as shown in  FIGS. 13 and 14 , an upper casing body  204 , which is a rotator, a through hole  206  formed in such a way that the outer driving gear  150  and the inner driving gear  146  can pass through in the central portion, an upper rotator slot  210  into which the upper rotator  220  is inserted, the upper cylinder  212  forming a moving space for plungers  278  and  280 , an upper contour closing seat  203  formed in the periphery of the upper casing body  204 , the inlet tube  214  and the outlet tube  216 . 
         [0147]    And in the upper rotator slot  210  is formed an upper closing seat  208  for an upper closer  218  to be positioned. 
         [0148]    Corresponding to the upper contour closing seat  203  of the upper casing  202  is formed a lower contour closing seat  274  in the lower casing  264 , and an outer contour closer  294  is placed between the upper contour closing seat  203  and the lower contour closing seat. 
         [0149]    It is preferable that either of the upper contour closing seat  203  and lower contour closing seat  274  is formed in a protruded shape so as to improve closing force by pressurizing the contour closer  294  to the other side. 
         [0150]    In addition, upper joint bosses  205  are formed outward of the upper casing body  204 , and lower joint bosses  276  are formed outward of the lower casing body  272  of the lower casing  264 , so the upper casing  202  and the lower casing  264  can be engaged by a fastening means such as bolts and nuts. 
         [0151]    The upper rotator  220  includes, as shown in  FIG. 15  and  FIG. 16 , an upper rotator body  222  whose top side is inserted into the upper rotator slot  210  and whose lower side is roundly formed so as to form the upper portion of the cylinder together with the upper cylinder  212 , and an upper pusher  230  which is formed monolithically on one side of the upper rotator body  222 . 
         [0152]    On the top side of the upper rotator  220  is formed an upper top side closing slot  224  where the upper closer  218  is positioned, and on the bottom side of the upper rotator  220  are protruded upper bottom side closing bosses  236  and  238  at intervals on the inside and outside of an upper bottom side closing slot  240  so as to form the upper bottom side closing slot  240  where the intermediate closer  242  is positioned. 
         [0153]    On both sides of the upper pusher  230  are formed upper insert bosses  232  and  234  so as to make it easy to fix on the plunger  278 . 
         [0154]    In addition, an outer driving gear joint hole  226  for the outer driving gear  150  to be engaged therewith, and an inner driving gear through hole  228  are formed in the center of the upper rotator  220  so that the inner driving gear  146  passes there through concentrically with the outer driving gear joint hole  226 . At this time, it is preferable that the outer driving gear joint hole  226  has a cross sectional area equal to or smaller than the outer driving gear  150  so that the outer driving gear is tightly fixed. And it is preferable that the inner gear through hole  228  has a cross section larger than the maximum diameter of the inner driving gear  146  so as to reduce contact area. 
         [0155]    The upper casing  202  includes, as shown in  FIG. 13  and  FIG. 14 , an upper casing body  204 , which is a rotator, a through hole  206  formed in such a way that the outer driving gear  150  and the inner driving gear  146  can pass through in the central portion of the upper casing body  204 , an upper rotator slot  210  into which the upper rotator  220  is inserted, and an upper cylinder  212  forming a moving space for the plungers  278  and  280 , the inlet tube  214  and the outlet tube  216 . 
         [0156]    As mentioned above, in the upper rotator slot  210  is formed the upper closing seat  208  for the upper closer  218  to be positioned. 
         [0157]    The lower rotator  244  includes, as shown in  FIG. 17  and  FIG. 18 , a lower rotator body  246  whose top side is roundly formed so as to form the lower portion of the cylinder together with the lower cylinder  270  and whose lower side is inserted into the lower rotator slot  268 , and a lower pusher  256  formed monolithically on one side of the lower rotator body  246 . 
         [0158]    On the upper side of the upper rotator  244  are protruded lower top side closing bosses  248  and  250  at intervals on the inside and outside of a lower top side closing slot  252  so as to form the lower top side closing slot  252  where the middle closer  242  is positioned, and on the lower side of the lower rotator  244  is formed a lower bottom side closing slot  262  where a lower closer  263  is positioned. 
         [0159]    On both sides of the lower pusher  256  are formed lower insert bosses  258  and  260  so as to make it easy to fix on the plunger  280 . 
         [0160]    And in the center of the lower rotator  244  is formed an inner driving gear joint slot  254  for joining an inner driving gear  146 . At this time, it is preferable that the inner driving gear slot  254  has a cross sectional area equal to or smaller than the inner driving gear  146  so that the inner driving gear  146  is tightly fixed. 
         [0161]    Next, the both ends of the plungers  278  and  280  are fixed on the upper pusher  230  and the lower pusher  256  as shown in  FIG. 19 . The plungers  278  and  280  have cross sectional areas equal to that of the cylinder which is formed, by being bent at the same radius of curvature, and its central angle is 30° as mentioned above. The central angle of the plungers  278  and  280  are the same as the central angle between the inlet tube  214  and the outlet tube  216 . 
         [0162]    And in the center of the plungers  278  and  280  is formed an insert slot  288  into which the upper pusher  230  or the lower pusher  256  is inserted, and on the left and right sides of the insert slot  288  are formed insert slots  290  and  292  which are engaged with upper insert bosses  232  and  234  or the lower insert bosses  258  and  260 . And on both sides of the outer circumference of the plungers  278  and  280  are inserted O-rings  282  and  284 , so that the plungers  278  and  280  can come into close contact with the inner wall of the cylinder. 
         [0163]    The lower casing  264  includes, as shown in  FIG. 20  and  FIG. 21 , a lower casing body  272 , which is a rotator, a lower rotator slot  268  into which the lower rotator  244  is inserted, and a lower cylinder  270  which forms a moving space for the plungers  278  and  280 . 
         [0164]    And in the lower rotator slot  268  is formed a lower closing seat  266  where the lower closer  263  can be positioned. 
         [0165]    Around the lower casing body  272  is formed the lower contour closing seat  274  as mentioned above, and outward of the upper casing body  204  are formed the upper joint bosses  205 , and outward of the lower casing body  272  are formed the lower joint bosses  276  to correspond to the upper joint bosses  205  of the upper casing  202 . 
         [0166]    The operating unit  200  is composed basically as mentioned above, and below will be described the assembled state and the operating method. 
         [0167]      FIG. 22  is a view schematically showing the sequence of operation of the operating unit  100 , after assembling the upper rotator  222  and lower rotator  244  of the operating unit  200 . 
         [0168]    As shown in  FIG. 22 , description will be given based on the lower casing  264 , and the inlet tube  214  and outlet tube  216  are installed in the upper casing  202 , but to make it easy to understand, it is illustrated in such a way that it communicates with the lower casing  264 . And the positions of the outlet tube and the inlet tube are for the case that the plungers  278  and  280  rotate clockwise; if the direction of rotation of the plungers  278  and  280  is counterclockwise, the drawing symbol  216  becomes the inlet tube and the drawing symbol  214  becomes the outlet tube. 
         [0169]    The product on the market is in a sealed state, and the plungers  278  and  280  shown in  FIG. 22   a  rotated a little further clockwise, so the plungers  278  and  280  have closed the outlet tube  216  and the inlet tube  214 . 
         [0170]    And the operation start state is, as shown in  FIG. 22   a , a state in which any one plunger  280  is positioned between the inlet tube  214  and the outlet tube  216  and the other plunger  278  has closed the inlet tube  214 . The operation state in a sealed condition starts through the operation of the driving device  100 . 
         [0171]    Next, when the plunger  280  starts to rotate clockwise as shown in  FIG. 22   b , negative pressure is generated in the cylinder, such that a liquid medication is introduced into the cylinder through the inlet tube  214 . And when it continues to rotate clockwise, the plunger  278  comes into contact with the plunger  280  which is positioned between the outlet tube  216  and the inlet tube  214 . Namely, the plunger  278  rotates 300°. In this state, the plunger  278  has closed the outlet tube  216 . 
         [0172]    And the preceding plunger  280  and the following plunger  278  rotate 30° clockwise simultaneously. Accordingly, as shown in  FIG. 22   d , the following plunger  278  is positioned between the outlet tube  216  and the inlet tube  214 . In this state, as shown in FIG.  22   e  and  FIG. 22   f , according as the plunger  280  rotates clockwise, the liquid medication in the cylinder that is positioned in the direction of rotation (clockwise) ahead of the plunger  280  is discharged through the outlet tube  216 . At the same time, the liquid medication flows into the rear side of the plunger  280  through the inlet tube  214  to fill in the cylinder. In other words, discharge and inlet of the liquid medication in the cylinder occur simultaneously by the rotating plunger  280 . 
         [0173]    And when the plunger  280  continues to rotate clockwise, the plunger  280 , as shown in  FIG. 22   g , comes into contact with the plunger  278  positioned between the outlet tube  216  and the inlet tube  214 . Namely, the plunger  280  rotates 300°. In this state, the plunger  280  has closed the outlet tube  216 . 
         [0174]    And the preceding plunger  278  and the following plunger  280  rotate 30° clockwise simultaneously and returns again to the state as shown in  FIG. 22   a.    
         [0175]    As mentioned above, if the plungers  278  and  280  make one rotation respectively, they carry out again the actions shown in  FIGS. 22   a  to  22   g  repetitively. Accordingly, the operating unit  200  can carry out the feeding of a liquid medication continuously, and minute regulation of the feed of the liquid medication is possible by controlling the rotation velocity of the plungers  278  and  280 . 
         [0176]    Below will be described the operating process of the operating unit  200  in relation to the operating device  100 . The plunger  280  is connected to the inner driving gear  146 , and the plunger  278  is connected to the outer driving gear  150   
         [0177]    Accordingly, when the outer driving gear  150  starts first to rotate in a state of  FIG. 22   a  and the outer driving gear  150  rotates 300°, the plunger  278  rotates clockwise and comes into contact with the plunger  280  positioned between the outlet tube  216  and the inlet tube  214 , as shown in  FIG. 22   c . In this state, when the outer driving gear  150  and the inner driving gear  146  rotate 30° simultaneously as mentioned above, the plunger  278  comes to be positioned between the outlet tube  216  and the inlet tube  214 , and the plunger  280  is pushed out toward the inlet tube  214 . 
         [0178]    And when the inner driving gear  146  rotates 300° again, the plunger  280  rotates 300° clockwise, so it comes into contact with the plunger  278  positioned between the outlet tube  216  and the inlet tube  214 , as shown in  FIG. 22   g . In this state, when the outer driving gear  150  and the inner driving gear  146  rotate 30° simultaneously as mentioned above, the plunger  280  comes to be positioned between the inlet tube  214  and the outlet tube  216 , and the plunger  278  is pushed out toward the inlet tube  214 . 
         [0179]    Accordingly, by the alternate rotation of the inner driving gear  146  and the outer driving gear  150  of the operating device  100 , the above-mentioned process is repeated, so that the feeding of a liquid medication of the operating unit  200  is made continuously. 
         [0180]    And the displacement of the plungers  278  and  280  due to positive pressure and negative pressure generated between the plungers  278  and  280  can be controlled by the position retainers  133  and  137  mentioned above, so it is possible to feed a liquid medication constantly at all times. 
         [0181]    Although the present invention has been described in connection with the exemplary embodiments illustrated in the drawings, it is only illustrative. It will be understood by those skilled in the art that various modifications and equivalents can be made to the present invention. Therefore, the true technical scope of the present invention should be defined by the appended claims.