Abstract:
A liquid-dispensing structure includes: an outer cylinder with a one-way valve at its lower end to allow a liquid to flow into the outer cylinder; a hollow piston being slidable inside the outer cylinder and having a pair of liquid-tight portions formed with circular convex portions around its outer circumferential surface in positions apart in an axial direction; and an inner cylinder for dispensing a liquid, which reciprocates inside the outer cylinder so that the piston moves in a piston-sliding area of the inner cylinder having an opening through which the liquid flows. The opening is closed when the piston is at a lower position and is opened when the piston is at an upper position.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a cylinder mechanism used for, for example, a fluid container such as a cosmetic container. Further, the present invention relates to a valve mechanism used for a container for a fluid or a liquid such as cosmetics. 
   As such cylinder mechanisms, conventionally, a mechanism using a cylinder filled with a fluid therein and a piston sliding inside the cylinder is used. 
   In the conventional cylinder mechanisms, it was difficult to reciprocate a piston smoothly while accomplishing sufficient liquidtightness. Additionally, to achieve a configuration in which a piston can be reciprocated smoothly while accomplishing liquidtightness, the piston needs to be manufactured with an extremely high degree of accuracy, which increases production costs. 
   For this reason, the use of a configuration for moving a piston smoothly while accomplishing high liquidtightness by providing an O-ring contacting an inner circumferential surface of a cylinder on an outer circumferential surface of the piston, can be considered. 
   If this configuration is adopted, however, the shaft core of the piston tilts against the shaft core of the cylinder when the direction of a stress to the piston and the direction of the shaft core of the piston are not accurately the same. After the tile occurs, the piston may not be reciprocated. 
   With regards to valve mechanisms, as described in Japanese Patent Laid-open No. 2001-179139, conventionally, a valve mechanism having a spherical valve body and a spring for giving momentum to the valve body toward a valve seat is used. 
   In the above-mentioned conventional valve mechanism, it is preferred that a size of a passage portion through which a liquid passes can be altered according to a coefficient of viscosity of a liquid passing therethrough. The conventional valve mechanism, however, has a problem in that it is difficult to alter a size of the liquid passage portion discretionally. Additionally, the above-mentioned conventional valve mechanism has another problem in that comprising all parts of the valve mechanism by molded resins is difficult. 
   Further, as in Japanese Patent Laid-open No. 2001-179139, conventionally, a valve mechanism having a spherical valve body and a spring for giving momentum to the valve body toward a valve seat is used. Manufacturing costs of the valve mechanism using the spherical valve body and the spring, however, tends to be high. 
   For this reason, a valve mechanism having a resinous valve seat and a resinous valve body moving between a closed position contacting the valve seat and an open position separating from the valve seat is commonly used. 
   This valve mechanism using the resinous valve seat and valve body has a configuration in which a liquidtight position is formed with the valve seat and the valve body making surface contact. Consequently, when the contact portions of both the valve seat and the valve body is not manufactured in high accuracy, high liquidtightness cannot be accomplished. To manufacture the contact portions of the valve seat and the valve body in high accuracy, manufacturing costs of the valve seat and the valve body increase. 
   SUMMARY OF THE INVENTION 
   The present invention has been achieved in light of the above-mention problems, and an embodiment of the invention aims at providing a cylinder mechanism of a fluid container by which a piston can be reciprocated smoothly with a small force while accomplishing sufficient liquidtightness. Further, in another embodiment, the present invention aims at providing a valve mechanism for which the use of molded resins is possible, low costs can be realized and a size of the passage portion can be altered easily according to the coefficient of viscosity of a liquid passing through. Additionally, in still another embodiment, while keeping manufacturing costs low, it aims to provide a valve mechanism of a liquid container, which can accomplish high liquidtightness. 
   More specifically, one aspect of this invention involves liquid-dispensing structures described below. Solely for the sake of easy understanding and convenience, numerals indicated in the figures are referred to when describing various embodiments, but the invention is not limited to the numerals and the figures and also is not limited to the embodiments. 
   In an embodiment, a liquid-dispensing structure comprises: (I) an outer cylinder (e.g.,  23 ,  23 ′) to be filled with a liquid, said outer cylinder having a one-way valve (e.g.,  86 ) at its lower end to allow a liquid to flow into the outer cylinder; (II) a hollow piston (e.g.,  83 ) provided inside the outer cylinder, said piston having a pair of liquid-tight portions (e.g.,  114 ,  115 ) formed around its outer circumferential surface, each of which portions liquid-tightly contacts an inner circumferential surface (e.g.,  85 ) of the outer cylinder, said pair of liquid-tight portions being arranged in positions apart in an axial direction of the outer cylinder, said liquid-tight portions being circular convex portions; and (III) an inner cylinder (e.g.,  82 ) for dispensing the liquid, which reciprocates inside the outer cylinder in an axial direction of the inner cylinder which is co-axial with the outer cylinder, said inner cylinder having a piston-sliding area (e.g., S) where when the inner cylinder moves, the piston moves liquid-tightly with respect to the inner cylinder between a lower position and an upper position in the axial direction of the inner cylinder, said inner cylinder having an opening (e.g.,  91 ) which is closed when the piston is at the lower position and which is opened when the piston is at the upper position wherein the liquid inside the outer cylinder flows into an inside of the inner cylinder through the opening. 
   The above structures may include, but are not limited to, the following various specific configurations: 
   One of the pair of liquid-tight portions (e.g.,  114 ) may be provided at an upper end of the piston, and the other of the pair of liquid-tight portions (e.g.,  115 ) may be provided at a lower end of the piston. Further, the liquid-tight portion at the upper end may be formed with two circular convex portions (e.g.,  114 ), and the liquid-tight portions at the lower end may be formed with one circular convex portion (e.g.,  115 ). The liquid-tight portion provided at the upper end may be formed with an annular lip (e.g.,  112 ) extending upward, and the liquid-tight portion provided at the lower end may be formed with an annular lip (e.g.,  113 ) extending downward. 
   Each liquid tight portion of the piston may have a diameter larger than that of the inner circumferential surface of the outer cylinder, and the liquid tight portion (e.g.,  112 ,  113 ) maybe flexible inwardly. 
   The piston may have upper and lower circular convex portions (e.g.,  131 ,  132 ) along an inner circumferential surface (e.g.,  133 ) of the piston to close the opening (e.g.,  91 ) of the inner cylinder, wherein the upper and lower circular convex portions are arranged to locate the opening of the inner cylinder therebetween. 
   The inner cylinder may have at least one circular convex portion (e.g.,  1102 ,  1101 ) which is in contact liquid-tightly with the piston at the upper and lower positions in the piston-sliding area. In the above, the convex portion of the inner cylinder may have a U-shaped or V-shaped cross section. 
   Additionally, the one-way valve (e.g.,  86 ) may comprise: (a) a lower surface (e.g.,  85   a ,  85   a ″) extending from the inner circumferential surface (e.g.,  85 ) of the outer cylinder; (b) a central opening (e.g.,  41 ,  41 ″) provided in the lower surface; and (c) a valve body (e.g.,  89 ,  89 ″) movably placed in the central opening, said valve body comprising (i) a head portion (e.g.,  54 ) provided inside the outer cylinder, said head portion having a larger diameter than the central opening and being fitted on the lower surface to close the opening when the valve body is at a lower position, and (ii) a restraining portion (e.g.,  56 ) provided outside the outer cylinder, said restraining portion having a larger diameter than the central opening and having grooves (e.g.,  58 ) to flow the liquid therethrough when the valve body is at an upper position. 
   In the above, the lower surface may have at least one circular convex portion (e.g., equivalent to  57 ) which is in contact liquid-tightly with the head portion of the valve body at the lower position. Alternatively or additionally, the head portion (e.g.,  54 ) of the valve body may have a lower surface (e.g.,  152 ) having at least one circular convex portion (e.g.,  1104 ) which is in contact liquid-tightly with the lower surface. 
   In an embodiment, the one-way valve (e.g.,  86 ) may comprise: (a) a lower surface (e.g.,  85   a ′) extending from the inner circumferential surface of the outer cylinder, said lower surface having at least one opening (e.g.,  41 ′), through which the liquid flows; (b) a central tube body (e.g.,  52 ) provided in the lower surface; and (c) a valve body (e.g.,  89 ′) movably placed in the tube body, said valve body comprising (i) a head portion (e.g.,  54 ′) provided inside the outer cylinder, said head portion being fitted on the lower surface to close the opening (e.g.,  41 ′) when the valve body is at a lower position, and (ii) a restraining portion (e.g.,  56 ′) provided outside the outer cylinder, said restraining portion having a larger diameter than the tube body to prevent the valve body from moving beyond an upper position. 
   In the above, the lower surface may have at least one circular convex portion (e.g.,  57 ) which is in contact liquid-tightly with the head portion of the valve body at the lower position. Alternatively or additionally, the head portion of the valve body may have a lower surface (e.g.,  152 ′) having at least one circular convex portion (e.g., equivalent to  1104 ) which is in contact liquid-tightly with the lower surface. 
   In another embodiment, a liquid-dispensing structure may comprise: (a) an outer cylinder (e.g.,  23 ′) to be filled with a liquid, said outer cylinder having a one-way valve (e.g.,  89 ′) at its lower end to allow a liquid to flow into the outer cylinder; and (b) a piston (e.g.,  83 ) provided with an inner cylinder (e.g.,  82 ) inside the outer cylinder for dispensing the liquid, said one-way valve comprising: (I) a lower surface (e.g.,  152 ′) extending from an inner circumferential surface (e.g.,  85 ) of the outer cylinder, said lower surface having at least one opening (e.g.,  41 ′), through which the liquid flows; (II) a central tube body (e.g.,  52 ) provided in the lower surface; and (III) a valve body (e.g.,  89 ′) movably placed in the tube body, said valve body comprising (i) a head portion (e.g.,  54 ′) provided inside the outer cylinder, said head portion being fitted on the lower surface to close the opening when the valve body is at a lower position, and (ii) a restraining portion (e.g.,  56 ′) provided outside the outer cylinder, said restraining portion having a larger diameter than the tube body to prevent the valve body from moving beyond an upper position. In the above, the lower surface may have at least one circular convex portion (e.g.,  57 ) which is in contact liquid-tightly with the head portion of the valve body at the lower position. Alternatively or additionally, the head portion of the valve body may have a lower surface having at least one circular convex portion (e.g., equivalent to  1104 ) which is in contact liquid-tightly with the lower surface. 
   The present invention may also include a liquid container which may comprise a liquid dispenser (e.g.,  1 ) provided with the liquid-dispensing structure of any of the forgoing, and a container body (e.g.,  4 ) to which the liquid dispenser is attached. In the above, the container body may have a bottom (e.g.,  16 ) liquid-tightly provided inside the container body, said bottom being slidable against an inner circumferential surface (e.g.,  5 ) of the container body as inside pressure of the container body changes. 
   For purposes of summarizing the invention and the advantages achieved over the related art, certain objects and advantages of the invention have been described above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. 
   Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features of this invention will now be described with reference to the drawings of preferred embodiments which are intended to illustrate and not to limit the invention. 
       FIG. 1  is a schematic diagram illustrating a longitudinal section of a fluid container to which the cylinder mechanism according to an embodiment of the present invention applies. 
       FIG. 2  is a schematic diagram illustrating a longitudinal section of a fluid container to which the cylinder mechanism according to an embodiment of the present invention applies. 
       FIG. 3  is a schematic diagram illustrating a longitudinal section of a fluid container to which the cylinder mechanism according to an embodiment of the present invention applies. 
       FIGS. 4(A) and 4(B)  are a schematic diagram illustrating an enlarged view of the first piston  16 . 
       FIG. 5  shows the first piston  16  by further enlarging it. 
       FIGS. 6(A) and 6(B)  are a schematic diagram illustrating an enlarged view of the second piston  83 . 
       FIG. 7  is a schematic diagram illustrating a longitudinal section of a liquid container to which the valve mechanism  86  according to an embodiment of the present invention applies. 
       FIG. 8  is a schematic diagram illustrating an enlarged view of the relevant part of a liquid container to which the valve mechanism  86  according to an embodiment of the present invention applies. 
       FIG. 9  is a schematic diagram illustrating an enlarged view of the relevant part of a liquid container to which the valve mechanism  86  according to an embodiment of the present invention applies. 
       FIG. 10  is a schematic diagram illustrating an enlarged view of the relevant part of a liquid container to which the valve mechanism  86  according to an embodiment of the present invention applies. 
       FIGS. 11(A) and 11(B)  are a schematic diagram illustrating an enlarged illustration of the valve mechanism  86 . 
       FIG. 12  is a schematic diagram illustrating a longitudinal sectional view of a liquid container to which the valve mechanism  86  according to an embodiment of the present invention applies. 
       FIG. 13  is a schematic diagram illustrating an enlarged view of the relevant part of the liquid container to which the valve mechanism  86  according to an embodiment of the present invention applies. 
       FIG. 14  is a schematic diagram illustrating an enlarged view of the relevant part of the liquid container to which the valve mechanism  86  according to an embodiment of the present invention applies. 
       FIG. 15  is a schematic diagram illustrating an enlarged view of the relevant part of the liquid container to which the valve mechanism  86  according to an embodiment of the present invention applies. 
       FIG. 16  is a schematic diagram illustrating an enlarged sectional view of the vicinity of the valve mechanism  87 . 
       FIG. 17  is a schematic diagram illustrating an enlarged sectional view of the vicinity of the valve mechanism  87 . 
       FIG. 18  is a schematic diagram illustrating an enlarged illustration of the valve mechanism  86 . 
       FIGS. 19  is a schematic diagram illustrating an enlarged illustration of the valve mechanism  86  according to another embodiment. 
       FIGS. 20(A) ,  20 (B), and  20 (C) show illustrations of modified versions of the protruding portion  1101 . 
   

   Explanation of symbols used is as follows:  1 : Fluid discharge pump;  2 : Nozzle head: Outer lid;  4 : Fluid storing portion;  11 : Discharge portion;  12 : Pressing portion  14 : screw material;  15 : First cylinder;  16 : First piston;  17 : Outer lid;  18 : Air hole;  23 : Second cylinder;  24 : Coil spring;  41 : Opening portion;  81 : First coupling tube;  82 : Second coupling tube;  83 : Second piston;  86 : First valve mechanism;  87 : Second valve mechanism  89 : Valve body;  91 : Opening portion;  92 : Convex portion. 
   Further,  23 ′: Second cylinder;  41 ′: Opening portion;  51 : Bottom portion;  52 : Cylinder portion;  53 : Coupled portion;  54 ′: Valve portion;  55 ′: Guide portion;  56 ′: Regulating portion ;  57 : Protruding portion;  81 ′: First coupling tube;  89 ′: Valve body;  110 : Lid material  111 : Base;  112 : Lid body;  113 : Opening;  114 : Closed portion;  115 : Female screw portion  120 : Valve body;  130 : Cylindrical material;  133 : Opening portion;  151 : Bottom portion or tapered portion;  152 : Cylindrical portion;  153 : Coupled portion or Regulating portion;  154 ′: Valve portion;  155 ′: Guide portion;  156 ′: Regulating portion;  157 : Protruding portion. 
   Additionally,  23 ″: Second cylinder;  41 ″: Opening portion;  82 : Second coupling tube  83 : Second piston;  86 : Valve mechanism;  87 : Valve mechanism;  89 ″: Valve body;  1101 : Protruding portion;  1102 : Protruding portion;  103 : Protruding portion;  1104 : Protruding portion;  201 : Protruding portion;  300 : Protrusion;  301 : Protrusion. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present invention can be achieved in various ways including, but not following embodiments, and any combination of elements and configurations can be used in the present invention. 
   In a first embodiment of the present invention, a cylinder mechanism of a comprises a cylinder filled with a fluid inside it and a piston reciprocating inside the cylinder, which is characterized in that, on an outer circumferential surface of the piston, a pair of liquidtight portions, each of which contacts an inner circumferential surface of the cylinder, are arranged in positions apart only by a certain distance and the contact portions in a pair of the liquidtight portions, which contact the inner circumferential surfaces of the cylinder, comprise a pair of convex portions arranged adjacently. 
   In a second embodiment, a cylinder mechanism of a fluid container comprises a cylinder filled with a fluid inside it and a piston reciprocating inside the cylinder, which is characterized in that, on an outer circumferential surface of the piston, a pair of liquidtight portions, each of which contacts an inner circumferential surface of the cylinder, are arranged in positions apart only by a certain distance and that, of a pair of the liquidtight portions, the contact portion of one liquidtight portion, which contacts the inner circumferential surface of the cylinder, comprises a pair of convex portions arranged adjacently, and the contact portion of the other liquidtight portion, which contacts the inner circumferential surface of the cylinder, comprises a single convex portion. 
   A third embodiment of the present invention is characterized by comprising: A cylindrical main unit with a bottom, which has an opening portion at its bottom; a cylindrical portion having an external form smaller than the internal diameter of the opening portion at the main unit; a valve seat having a coupled portion, which couples the main unit and the cylindrical portion for fixing the cylindrical portion within the opening portion; a valve body having a valve portion which closes the opening portion by contacting the bottom of the main unit and opens the opening portion by separating from the bottom of the main unit, a guide portion having an external form smaller than the internal diameter of the cylindrical portion and a length longer than that of the cylindrical portion, which, by being inserted inside the cylindrical portion, guides a movement between a position at the valve portion which contacts the bottom of the main unit and a position which separates from the bottom, and a regulating portion for preventing the guide portion from coming off form the cylindrical body. In the above, at the portion which contacts the valve body at the valve seat, a protruding portion may be formed, and the valve seat and the valve body may contact each other via the protruding portion. 
   In a fourth embodiment, a valve mechanism has a valve seat and a valve body which moves between a closed position contacting the valve seat and an open position separating from the valve seat, which is characterized in that by forming a circular protruding portion in either of the valve seat or the valve body, the valve seat and the valve body are contacted via the circular protruding portion. In the forgoing, the circular protruding portion may have a nearly V-shaped cross-section. In variations, the circular protruding portion may have a nearly U-shaped cross-section. Further, the circular protruding portion may have a configuration in which a circular protrusion is provided doubly. 
   The first and second embodiments are described by referring to figures.  FIGS. 1 to 3  are longitudinal sections of a fluid container to which the cylinder mechanism according to the present invention applies. 
   Of the figures,  FIG.1  position in which no stress is given to a fluid discharge pump  1  shows a position in which, with a pressing portion  1  at a nozzle head  2  being pressed, the first and the second coupling tubes  81  and  82  are descending along with the second piston  83 .  FIG. 3  shows with a pressure applied to the nozzle head being released, the first and the second coupling tubes  81  and  82  ascending along with the second piston  83 . In  FIG. 1  to  FIG. 3 , clearly demonstrate an opening portion  91 , hatching is added only to the second coupling tube  82  respectively. 
   This fluid container is used as a container for beauty products for storing gels such as hair gels and cleansing gels or creams such as nourishing creams and cold creams or liquids such as skin toners used in the cosmetic field. Additionally, in this specification, high-viscosity liquids, semifluids, gels that sol solidifies to a jelly, and creams, and regular liquids, are all referred to as fluids. 
   This fluid container comprises a fluid discharge pump  1 , a nozzle head  2 , an outer lid  3  and a fluid storing portion  4  for storing a fluid inside it. 
   The nozzle head  2  has a discharge portion  11  for discharging a fluid and a pressing portion  12  to be pressed when the fluid is discharged. Additionally, the outer lid  3  is engaged with a screw portion formed at the top edge of the fluid storing portion  4  via a screw material  14 . 
   The fluid storing portion  4  has the first cylinder  15  which is tubular, the first piston  16  which moves in upward and downward directions inside the first cylinder  15  and an outer lid  17  number of air holes  18  are provided. The first cylinder  15  and the fluid discharge pump  1  are connected by packing  19 . 
   The first piston  16  configuration to move smoothly inside the first cylinder  15  while accomplishing high liquidtightness. The configuration of the first piston  16  is described later in detail. 
   In this fluid container, by pressing the pressing portion  12  at the nozzle head  2  to generate reciprocating motions in upward and downward directions, a fluid stored inside the fluid storing portion  4  is discharged from the discharge potion  11  at the nozzle head  2  by the action of the fluid discharge pump  1  which is described later in detail. As an amount of the fluid inside the fluid storing portion  4  reduces, the first piston  15  moves inside the first cylinder  15  toward the nozzle head  2 . 
   In this specification, upward and downward directions in  FIGS. 1 to 3  are defined as upward and downward directions in the fluid container. In other words, in the fluid container according to this embodiment, the side of the nozzle head  2  shown in  FIG. 1  is defined as the upward direction, and the side of the first piston  16  is defined as the downward direction. 
   The configuration of the fluid discharge pump  1  is described below. 
   This fluid discharge pump  1  possesses: second cylinder  23 ; the second piston  83  which can reciprocate inside the second cylinder  23 ; the first and the second hollow coupling tubes  81  and  82  coupled and fixed with each other to form a coupling tube, which is used for sending down the second piston  83  by transmitting a pressure given to the nozzle head  2  to the second piston  83 , by coupling the nozzle head  2  and the second piston  83 ; a coil spring  24  set up at the outer perimeter of the first and the second coupling tubes  81  and  82  for giving momentum to the second piston  83  in the direction of raising it; the first valve mechanism  86  for flowing a fluid stored in the fluid storing portion  4  into the second cylinder  23  as the second piston  83  ascends; the second valve mechanism  87  for letting the fluid flowed into the second cylinder  23  out to the nozzle head  2  through the first and the second coupling tubes  81  and  82  as the second piston  83  descends. 
   Similarly to the first piston  16 , the second piston  83  mentioned above requires a configuration to move smoothly inside the second cylinder  23  while accomplishing high liquidtightness. The configuration of the second piston  83  is described later in detail. 
   For the coil spring  24  mentioned above, a metal coil spring is used to acquire strong momentum. Because this coil spring  24  is set up at the outer perimeter of the coupling tube  81 , it does not contact the fluid passing through the inside of the coupling tube  81 . 
   The above-mentioned the first valve mechanism  86  is used to close an opening portion  41  communicating with the fluid storing portion  4  formed in the vicinity of the lower end of the second cylinder  23  and the second cylinder  23  when a pressure is applied to inside the second cylinder  23 , and to open the opening portion  41  when inside the second cylinder  23  is depressurized. 
   The first valve mechanism  86  has a tapered portion slanted by an angle equal to the angle of a tapered inner surface at the lower end of the second cylinder  23  and possesses a resinous valve body  89  having a stopper formed at its lower end. In this first valve mechanism  86 , when inside the second cylinder  23  is pressurized, the opening portion  41  is closed with the tapered portion of the valve body  89  contacting an inner tapered portion at the lower end of the second cylinder  23  as shown in  FIG. 2 . When inside the second cylinder  23  is depressurized, the opening portion  41  is opened with the tapered portion of the valve body  89  separating from an inner tapered portion at the lower end of the second cylinder  23  as shown in  FIG. 3 . At this time, a traveling distance of the valve body  89  is controlled by the stopper formed at the lower end of the valve body  89  contacting the lower end of the second cylinder  23 . 
   In the stopper formed at the lower end of the valve body  89 , a notch portion (not shown in the figures) is formed. Consequently, as shown in  FIG. 3 , when the stopper contacts the lower end of the second cylinder  23 , the configuration makes it possible that the fluid can flow in from the lower end of the opening portion of the second cylinder  23 . 
   The above-mentioned second valve mechanism  87  is used to open a flow path communicating with inside the first and the second coupling tubes  81  and  82  and inside the second cylinder  23  by separating from the above-mentioned second piston  83  when the nozzle head  2  is pressed, and to close the flow path communicating with inside the first and the second coupling tubes  81  and  82  inside the second cylinder  23  by contacting the second piston  83  when a pressure to the nozzle head  2  is removed. 
   Down below the cylindrical portion of the second coupling tube  82 , an opening portion  91  is provided Additionally, outside the opening portion  91 , a convex portion  92  which can contact a concave portion formed in the second cylinder  23  is formed. As shown in  FIG. 2 , in a position in which the concave portion formed in the second cylinder  23  and the convex portion formed in the second coupling tube  82  are separated, a flow path leading to inside the first and the second coupling tubes  81  and  82  from inside the second cylinder  23  through the opening portion  91  is formed. As shown  FIG. 1  and  FIG. 3 , in a position in which the concave portion formed in the second cylinder  23  and the convex portion formed in the second coupling tube  82  are contacted, a flow path leading to inside the first and the second coupling tubes  81  and  82  from inside the second cylinder  23  is closed. 
   Discharge motions of the fluid discharge container possessing the above-mentioned fluid discharge pump  1  are described below. 
   In an initial position, as shown in  FIG. 1 , momentum is given to the first and the second coupling tubes  81  and  82  coupled with each other in an upward direction by the action of the coil spring  24 , and the convex portion  92  formed at the lower end of the second coupling tube  82  contacts the concave portion formed in the second piston  83 . Consequently, a flow path leading to inside the first and the second coupling tubes  81  and  82  from inside the second cylinder  23  is closed. Additionally, by the empty weight of the valve body  89 , the tapered portion of the valve body  89  contacts the inner tapered portion at the lower end of the second cylinder  23 , closing the opening portion  41 . 
   In this position, when the pressing portion  12  at the nozzle head  2  is pressed, as shown in  FIG. 2 , the first and the second coupling tubes  81  and  82  first descend relatively to the second piston  83 . By this motion, the convex portion  92  formed at the lower end of the second coupling tube  82  separates from the concave potion formed in the second piston  83 . Consequently, a flow path leading to inside the first and the second coupling tubes  81  and  82  from inside the second cylinder  23  through the opening  91  is formed. 
   If the pressing portion  12  at the nozzle head  2  is pressed further, the lower end of the second coupling tube  81  and the top of the second piston  83  are contacted, and the second piston  83  and the first and the second coupling tubes  81  and  82  descend all together. At this time, inside the second cylinder is pressurized, and the opening  41  is closed with the tapered portion of the valve body  89  contacting the inner tapered portion at the lower end of the second cylinder  23 . Consequently, the pressurized fluid inside the second cylinder  23  flows out to the discharge portion  11  at the nozzle head  2  through the opening portion  91  and the first and the second hollow coupling tubes  81  and  82 , and is discharged from the discharge portion  11 . 
   After the second piston  83  descends to the lower limit of a stroke, if a pressure applied to the nozzle head  2  is removed, the first and the second coupling tubes  81  and  82  ascend by the action of the coil spring  24  relatively to the second piston  83 . By this motion, as shown in  FIG. 3 , the convex portion  92  formed at the lower end of the second coupling tube  82  contacts the concave portion formed in the second piston  83 . Consequently, the flow path leading to inside the first and the second coupling tubes  81  and  82  from inside the second cylinder  23  is closed again. 
   After that, the nozzle head  2 , the first and the second coupling tubes  81  and  82  and the second piston  83  ascend all together by the action of the coil spring  24 . At this time, because inside the second piston  23  is depressurized, the opening portion  41  is opened by the tapered portion of the valve body  89  separating from the inner tapered portion at the lower end of the second cylinder  23 , and the fluid flows into the second cylinder  23  from the fluid storing portion  4  through the notch portion formed in the stopper. As shown in  FIG. 3 , if the second piston  83  moves to the upper limit of its elevating stroke, it stops to ascend. 
   By repeating the above-mentioned motions, discharging the fluid stored in the fluid storing portion  4  from the nozzle head  2  becomes possible. 
   The configurations of the first and the second piston  16  and  83 , which are characteristic of the present invention, are described below. 
   The configuration of the first piston  16  is first described.  FIGS. 4(A) and 4(B)  show enlarged views of the above-mentioned first piston  16 .  FIG. 4(A)  is a lateral view of the first piston  16 .  FIG. 4(B)  is a cross-section of the first piston  16 .  FIG. 5  shows a cross-section of the first piston  16  by further enlarging it. 
   At the top of the first piston  16 , a liquid portion  102  contacting the inner circumferential portion of the first cylinder  15  is formed the bottom of the first piston  16 , a liquidthight portion  103  contacting the inner circumferential portion of the first cylinder  15  is formed. In other words, in the outer circumferential surface of the first piston  16 , a pair of liquidtight portions  102  and  103  which contact the inner circumferential surfaces are arranged in positions apart only by a certain distance. 
   A portion contacting the inner circumferential surface of the fist cylinder  15  in the liquidtight portion  102  comprises pair of convex portions  104  and  104 ′ arranged adjacently. A portion contacting the inner circumferential surface of the first cylinder  15  in the liquidtight portion  103  comprises a pair of convex portions  105  and  105 ′ arranged adjacently. These convex portions  104   s  and  105   s  have a nearly round cross-sectional surface as shown in  FIG. 5  after magnification. 
   In this first piston  16 , by the action of a pair of liquidtight potions  102  and  103  arranged in positions apart only by a certain distance, the shaft core of the first piston and the shaft core of the first cylinder  15  can be brought in line at all the times regardless of the direction of a stress applied to the first piston, making it possible to move the first piston  16  smoothly inside the first cylinder  15 . 
   Because the contact portions in a pair of liquidtight portions  102  and  103 , which contact the inner circumferential surfaces of the first cylinder  15 , comprises a pair of convex portions  104  and  104 ′, liquidtight performance can be doubled while a contact area of the first piston  16  inside the first cylinder  15  is reduced, making it possible to move the first piston  16  inside the first cylinder  15  using a small force while accomplishing sufficient liquidtightness. 
   The configuration of the second piston  83  is described below.  FIGS. 6(A) and 6(B)  are an enlarged view of the above-mentioned second piston  83 .  FIG. 6(A)  is a lateral view of the second piston  83 .  FIG. 6(B)  shows a cross-section of the second piston  83 . 
   At the top of this second piston  83 , a liquidtight portion  112  which contacts the inner circumferential surface of the second cylinder  23 , is formed. At the bottom of the second piston  83 , a liquidtight portion  113 , which contacts the inner circumferential surface of the second piston  23 , is formed. In other words, in the outer circumferential surface of the second piston  83 , a pair of liquidtight portions  112  and  113 , which contact respective inner circumferential surfaces of the second piston  83 , are arranged in positions apart only by a certain distance. 
   The contact portion in the liquidtight portion  112 , which contacts the inner circumferential surface of the second cylinder  23 , comprises a pair of convex portions  114  and  114 ′ arranged adjacently; the contact portion in the liquidtight portion  113 , which contacts the inner circumferential surface of the second cylinder  23 , comprises a single convex portion  115 . These convex portions  114   s  and  115  have a nearly round cross-sectional surface. 
   In the air holes of the second coupling tube  82  in the second piston  83 , a convex portion  121  is formed to increase liquidtightness of the second piston  83  and the second coupling tube  82 . 
   in this second piston  83 , similarly to the first piston, by the action of a pair of the liquidtight portions  112  and  113  arranged in positions apart only by a certain distance, regardless of the direction of a stress applied to the second piston  83 , the shaft core and the second piston and the shaft core of the second cylinder can be brought in line at all the times, making it possible to move the second piston  83  smoothly inside the second cylinder  23 . 
   Because the contact portion in the other liquidtight portion  112 , which contacts the inner circumferential surface of the second cylinder  23 , comprises a pair of convex portions  114  and  114 ′ arranged adjacently, liquidtightness performance can be doubled while a contact area of the second piston  83  and the second cylinder  23  is reduced, making it possible to move the second piston  83  inside the second cylinder  23  using a small force while accomplishing sufficient liquidtightness. 
   The other liquidtight portion  113  comprises a single convex portion  115 , which is inferior in liquidtightness as compared with a pair of convex portions arranged adjacently. Nevertheless, the liquidtight function of the second cylinder  23  is secured by the other liquidtight portion  112 . 
   In the above-mentioned embodiment, as the convex portions  104   s ,  105 ,  114  and  115 , those having a nearly round section shape are used. A convex portion having a polygonal shape or having its edge pointed also can be adopted. 
   In the above-mentioned embodiment, the cases in which the present invention applies to fluid containers used as containers for cosmetics were described. The present invention, however, also can be applied to containers used for food and drinks, etc. 
   As explained above, the forgoing embodiments exhibit the following effects: By the action of a pair of the liquidtight portions arranged in positions apart only by a certain distance, the shaft core of the piston and the shaft core of the cylinder can be brought in line at all the times, making it possible to move the piston smoothly inside the cylinder. 
   Because the contact portion in at least one liquidtight portion, which contacts the inner circumferential surface of the cylinder, comprises a pair of convex portions arranged adjacently, liquidtight performance can be doubled while a contact area of the piston and the cylinder is reduced, making it possible to move the piston inside the cylinder using a small force while accomplishing sufficient liquidtightness. 
   The third embodiment of the present invention is described in detail by referring to figures.  FIG. 7  shows a longitudinal section of a liquid container to which the valve mechanism  86  according to the first embodiment of the present invention applies.  FIG. 8  to  FIG. 10  show enlarged views of its relevant part. 
   Of these figures,  FIG. 7  and  FIG. 8  show positions in which no stress is given to a liquid discharge pump  1 .  FIG. 9  shows a position in which the first and the second coupling tubes  81 ′ and  82  descend along with the second piston  83  with the pressing portion  12  at a nozzle head  2  being pressed.  FIG. 10  shows a position in which the first and the second coupling tubes  81 ′ and  82  ascend along with the second piston  83  with a pressure applied to the nozzle head  2  being released. 
   This fluid container is used as a container for beauty products for storing gels such as hair gels and cleansing gels or creams such as nourishing creams and cold creams or liquids such as skin toners used in the cosmetic field. This liquid container also can be used as a container for medicines, solvents or foods, etc. In this specification, high-viscosity liquids, semifluids, gels that sol solidifies to a jelly, and creams, and regular liquids, are all referred to as fluids. 
   This liquid container comprises a liquid discharge pump  1 , a nozzel head  2 , an outer lid  3  and a liquid storing portion  4  for storing a liquid inside it. 
   The nozzle head  2  has a discharge portion  11  for discharging a liquid and a pressing portion  12  which is pressed when the liquid is discharged. Additionally, the outer lid  3  is engaged with a screw portion formed at the top of the liquid storing portion  4  via a screw material  14 . 
   The liquid storing portion  4  has the first cylinder  15  which is cylindrical, the first piston  16  which moves inside the first cylinder  15  is upward and downward directions, and an outer lid  17  in which a number of air holes  18  are provided. The first cylinder  15  at the liquid storing portion  4  and the liquid discharge pump  1  are connected in a liquidtight position via packing  19 . 
   In this liquid container, by pressing the pressing portion  12  at the nozzle head  2 , reciprocating motions are generated by the action of the liquid discharge pump  1 . By these motions, a liquid stored in the liquid storing portion  4  is discharged from the discharge portion  11 . As an amount of the liquid inside the liquid storing portion  4  reduces, the first piston  16  moves in side the first cylinder  15  toward the nozzle head  2 . 
   In this specification, upward and downward directions in  FIGS. 7 to 10  are defined as upward and downward directions in the fluid container. In other words, in the fluid container according to this embodiment, the side of the nozzle head  2  shown in  FIG. 7  is defined as the upward direction, and the side of the first piston  16  is defined as the downward direction. 
   The configuration of the fluid discharge pump  1  is described below. 
   This fluid discharge pump  1  possesses: The second cylinder  23 ′; the second piston  83  which can reciprocate inside the second cylinder  23 ′; the first and the second hollow coupling tubes  81 ′ and  82  coupled and fixed with each other to form a coupling tube for sending down the second piston  83  by transmitting a pressure given to the nozzle head  2  to the second piston  83 , by coupling the nozzle head  2  and the second piston  83 ; a contact portion  92 ′ provided at the lower end of the second coupling tube  82 ; a coil spring  24  set up at the outer perimeter of the first and the second coupling tubes  81 ′ and  82  for giving momentum to the second piston  83  in the direction of raising it; the valve mechanism  86  according to the present invention for flowing a fluid stored in the fluid storing portion  4  into the second cylinder  23 ′ as the second piston  83  ascends; a closed mechanism  87  for letting the fluid which flowed into the second cylinder  23 ′ out to the nozzle head  2  through inside the first and the second coupling tubes  81 ′ and  82  as the second piston  83  descends. 
   The contact portion  92 ′ at the above-mentioned closed mechanism  87  is used to open a flow path communicating with inside the first and the second coupling tubes  81 ′ and  82  and inside the second cylinder  23 ′ by separating from the second piston  83  when the nozzle head  2  is pressed, and to close the flow path communicating with inside the first and the second coupling tubes  81 ′ and  82  and inside the second cylinder  23 ′ by contacting the second piston  83  when a pressure applied to the nozzle head  2  is removed. 
   Down below the cylindrical portion of the second coupling tube  82 , an opening portion  91  is shown in  FIG. 9 , in a position in which the lower end of the second piston  83  and the contact portion  92 ′ provided at the lower end of the second coupling tube  82  are separated, a flow path leading to inside the first and the second coupling tubes  81 ′ and  82  from inside the second cylinder  23 ′ through the opening portion  91  is formed. As shown  FIG. 8  and  FIG. 10 , in a position in which the lower end of the second piston  83  and the contact portion  92 ′ provided at the lower end of the second coupling tube  82  are contacted, the flow path leading to inside the first and the second coupling tubes  81 ′ and  82  from inside the second cylinder  23 ′ is closed. 
   The valve mechanism  86  according to the present invention is used to close an opening portion  41 ′ communicating with the liquid storing portion  4  formed in the vicinity of the lower end of the second cylinder  23 ′ and the second cylinder  23 ′ when inside the second cylinder  23 ′ is pressurized, and to open the opening portion  41 ′ when inside the second cylinder  23 ′ is depressurized. 
     FIGS. 11(A) and 11(B)  are an enlarged illustration of the valve mechanism  86 .  FIG. 11(A)  shows a lateral view of the valve mechanism  86 .  FIG. 11(B)  shows the bottom of the second cylinder  23 ′. 
   The valve mechanism  86  possesses the above-mentioned second cylinder  23 ′ which is a cylindrical main unit with a bottom and has the opening  41 ′ at its bottom  51 , a cylindrical portion  52  having an external form smaller than the internal diameter of the opening portion  41  ′ at the second cylinder  23 ′, and a valve seat having a coupled portion  53 , which couples the second cylinder  23 ′ and the cylindrical portion  52  for fixing the cylindrical portion  52  within the opening portion  41 ′. 
   At a portion at the second cylinder  23 ′, which contacts a valve body  89 ′ described later of the second cylinder  23 ′, a protruding portion  57  is formed. Consequently, even when the manufacturing accuracy of the second cylinder  23 ′ or the valve body  89 ′ described later has deteriorated the valve body  89 ′ and the protruding portion  57  can be contacted reliably; as compared with cases in which a surface and a surface are contacted, maintaining higher liquidtightness becomes possible. 
   Additionally, this valve mechanism possesses the valve body  89 ′ having a valve portion  54 ′, which closes the opening portion  41 ′ by contacting the above-mentioned protruding portion  57  at the bottom  51  of the second cylinder  23 ′ and opens the opening portion  41 ′ by separating from the protruding portion  57  at the bottom  51 , a guide portion  55 ′, which has an external form smaller than the internal diameter of the cylindrical portion  52  and a length longer than that of the cylindrical portion  52 , and which, by being inserted inside the cylindrical portion  52 , guides a movement between a position at the valve portion  57  which contacts the protruding portion  57  at the bottom  51  and a position which separates from the protruding portion  57 , and a regulating portion  56 ′ for preventing the guide portion  55 ′ from coming off from the cylindrical body  52 . 
   The above-mentioned valve seat and valve body  89 ′ are produced by molding polypropylene or polyethylene, or resin such as silicone rubber. 
   For the valve body  89 ′, a dividing groove is provided from its guide portion  55 ′ to its regulating portion  56 ′. By the action of the dividing groove, it becomes possible to press the regulating portion  56 ′ of the valve body  89 ′ into the cylindrical portion  52 , and after being pressed into, coming off of the guide portion  55 ′ from the cylindrical portion  52  can be prevented. 
   Discharge motions of the fluid discharge container possessing the above-mentioned fluid discharge pump  1  are designed below. 
   In an initial position, as shown in  FIG. 7  and  FIG. 8 , momentum is given to the first and the second coupling tubes  81 ′ and  82  coupled with each other in an upward direction by the action of the coil spring  24 , and the contact portion  92 ′ provided at the lower end of the second coupling tube  82  contacts the lower end of the second piston  83 . Consequently, a flow path leading to inside the first and the second coupling tubes  81 ′ and  82  from inside the second cylinder  23 ′ is closed. Additionally, by the empty weight of the valve body  89 ′, as shown in  FIGS. 11(A) and 11(B) , the valve portion  54 ′ of the valve body  89 ′ contacts the protruding portion  57  at the bottom  51  of the second cylinder  23 ′, closing the opening portion  41 ′. 
   In this position, when the pressing portion  12  at the nozzle head  2  is pressed, as shown in  FIG. 9 , the first and the second coupling tubes  81 ′ and  82  first descend relatively to the second piston  83 . By this motion, the contact portion  92 ′ formed at the lower edge of the second coupling tube  82  separates from the lower end of the second piston  83 . Consequently, the flow path leading to inside the first and the second coupling tubes  81 ′ and  82  from inside the second cylinder  23 ′ via the opening  91  is formed. 
   If the pressing portion  12  at the nozzle head  2  is pressed further, the lower end of the second coupling tube  81 ′ contacts the top of the second piston  83 , and the second piston  83  and the first and the second coupling tubes  81 ′ and  82  descend all together. At this time, inside the second cylinder  23 ′ is pressurized, and as shown in  FIGS. 11(A) and 11(B) , the opening  41 ′ is closed with the valve portion  54 ′ of the valve body  89 ′ contacting the protruding portion  57  at the lower end  51  of the second cylinder  23 ′. Consequently, the pressurized fluid inside the second cylinder  23 ′ flows out to the discharge portion  11  at the nozzle head  2  through the opening portion  91 , and the first and the second hollow coupling tubes  81 ′ and  82 , and is discharged from the discharge portion  11 . 
   After the second piston  83  descends to the lower limit of a stroke, if a pressure applied to the nozzle head  2  is removed, the first and the second coupling tubes  81 ′ and  82  ascend relatively to the second piston  83  by the action of the coil spring  24 . By this motion, as shown in  FIG. 10 , the contact portion  92 ′ provided at the lower end of the second coupling tube  82  contacts the lower end of the second piston  83 . Consequently, the flow path leading to inside the first and the second coupling tubes  81 ′ and  82  from inside the second cylinder  23 ′ is closed again. 
   After that, the nozzle head  2 , the first and the second coupling tubes  81 ′ and  82  and the second piston  83  ascend all together by the action of the coil spring  24 . At this time, because inside the second piston  23 ′ is depressurized, the opening portion  41 ′ is opened by the valve portion  54 ′ of the valve body  89 ′ separating from the protruding portion  57  at the bottom  51  of the second cylinder  23 ′, and the fluid flows into the second cylinder  23 ′ from the fluid storing portion  4 . If the second piston  83  moves to the upper limit of its elevating stroke, it stops to ascend. 
   By repeating the above-mentioned motions, discharging the fluid stored in the fluid storing portion  4  from the nozzle head  2  becomes possible. 
   In these liquid containers, it is preferred to alter a size of a passage portion through which a liquid passes according to a coefficient of viscosity of a liquid passing through it. In the above-mentioned valve mechanism, by altering a length of the guide portion  55 ′ at the valve body  89 ′, it becomes possible to set a size of the liquid passage portion, i.e. a size of an area between the valve portion  54 ′ of the valve body and the bottom  51  of the second cylinder, at a discretional value. 
   According to the forgoing, the use of molded resins is possible and costs can be reduced. Additionally, a size of the liquid passage portion can be easily altered according to a coefficient of viscosity of a liquid used. Further, even when high accuracy of a valve seat and a valve body has deteriorated, the valve seat and the valve body can be contacted reliably by the action or the protruding portion. 
   The fourth embodiment is described in detail by referring to figures.  FIG. 12  longitudinal section of a liquid container to which the valve mechanisms  86  and  87  according to the present invention applies.  FIG. 13  and  FIG. 15  enlarged views of the relevant part of the valve mechanisms. 
   Of these figures,  FIG. 12  and  FIG. 2  respectively show a position in which no stress is applied to a liquid discharge pump.  FIG. 14  shows a position in which with a pressing portion  12  in a nozzle head  2  being pressed, the first and the second coupling tubes  81 ′ and  82  are in the process of descending along with the second piston  83 .  FIG. 15  shows a position in which with the nozzle head  2  being opened, the first and the second coupling tubes  81 ′ and  82  are in the process of ascending along with the second piston  83 . 
   This liquid container is used as a container for beauty products for storing gels such as hair gels and cleansing gels or creams such as nourishing creams and cold creams or liquids such as skin toners used in the cosmetic field. This liquid container also can be used as a container for medicines, solvents or foods, etc. In this specification, high-viscosity liquids, semifluids, gels that sol solidifies to a jelly, and creams, and regular liquids, are all referred to as fluids. 
   This liquid container comprises a liquid discharge pump  1 , a nozzel head  2 , an outer lid  3  and a liquid storing portion  4  for storing a liquid inside it. 
   The nozzle head  2  has a discharge portion  11  for discharging a liquid and a pressing portion  12  to be pressed when the liquid is discharged. The outer lid  3  is engaged with a screw portion formed at the top of the liquid storing portion  3  via a screw material  14 . 
   The liquid storing portion  4  has the first cylinder  15  which is cylindrical, the first piston  16  which moves in upward and downward directions inside the first cylinder  15 , and an out lid  17  in which a number of air holes  18  are made. The first cylinder  15  in the liquid storing portion  4  and the liquid discharge pump  1  are connected in a liquidtight position via packing  19 . 
   In this liquidtight container, by the action of the liquid discharge pump  1 , which generates reciprocating motions by pressing the pressing portion  12  at the nozzle head  2 , a liquid stored inside the liquid storing portion  4  is discharged from the discharge portion  11  at the nozzle head. As an amount of the liquid inside the liquid storing portion  4  reduces, the first piston  16  moves inside the first cylinder  15  toward the nozzle head  2 . 
   In this specification, the upward and the downward directions described in  FIG. 12  to  FIG. 15  are prescribed as the upward and downward directions in the liquid container. In other words, in the liquid container according to this embodiment, the side of the nozzle head  2  shown in  FIG. 12  is defined as the upward direction, and the side of the first piston  16  is defined as the downward direction. 
   The configuration of the liquid discharge pump  1  is described below. 
   The liquid discharge pump  1  possesses: the second cylinder  23 ″; the second piston  83  which can reciprocate inside the second cylinder  23 ″; the first and the second hollow coupling tubes  81 ′ and  82  coupled and fixed with each other to form a coupling tube for sending down the second piston  83  by transmitting a pressure applied at the nozzle head  2  to the second piston  83 , by coupling the nozzle head  2  and the second piston  83 ; a contact portion  92 ′ provided at a lower end of the second coupling tube  82 ; a coil spring  24  arranged at an outer circumferential portion of the first and the second coupling tubes  81 ′ and  82  for giving momentum to the second piston  83  toward its ascending direction; a valve mechanism  86  according to the present invention for bringing a liquid stored in the liquid storing portion  4  into the second cylinder  23 ″ as the second piston  83  ascends. 
   The above-mentioned second piston  83  and the contact portion  92 ′ comprise the valve mechanism  87  according to the present invention for letting the liquid which flowed into the second cylinder  23 ″ out to the nozzle head  2  via inside the first and the second coupling tubes  81 ′ and  82  as the second piston  83  descends. 
   In other words, when the nozzle head  2  is pressed, the contact portion  92 ′ in the above-mentioned valve mechanism  87  separates from the second piston  83 , opening a flow path communicating with inside the first and the second coupling tubes  81 ′ and  82  and inside the second cylinder  23 ″; when a pressure applied to the nozzle head  2  is released, the contact portion  92 ′ contacts the second piston  83 , closing the flow path communicating with inside the first and the second coupling tubes  81 ′ and  82  and inside the second cylinder  23 ″. The contact portion  92 ′ in the valve mechanism  87  corresponds to the valve seat according to the present invention; the second piston  83  in the valve mechanism  87  corresponds to the valve body according to the present invention. 
     FIG. 16  and  FIG. 17  are expanded sectional views showing in the vicinity of the valve mechanism  87 . 
   As these figures show, at a portion at the contact portion  92 ′, which contacts the second piston  83 , a circular protruding portion  1101  is formed. Consequently, the contact portion  92 ′ and the second piston  83  contact via this protruding portion  1101 . Additionally, at a portion in the first coupling tube  81 ′, which contacts the second piston  83 , a circular protruding portion  1102  is also formed to increase liquidtightness in the valve mechanism  87 . 
   Down below the cylindrical portion of the second coupling tube  82 , an opening  91  is made. As shown in  FIG. 14  and  FIG. 17 , in a position in which the lower end of the second piston  83  and the contact portion provided in the lower end of the second coupling tube  82  are separated, a flow path leading to inside the first and the second coupling tubes  81 ′ and  82  from inside the second cylinder  23 ″ via the opening  91  is formed. 
   As shown in  FIG. 13 , and  FIG. 15  and  FIG.16 , in a position in which the lower end of the second piston  83  and the contact portion  92 ′ provided at the lower end of the second coupling tube  82  contact via the protruding portion  1101 , the flow path leading to inside the first and the second coupling tubes  81 ′ and  82  from inside the second cylinder  23 ″ is closed. 
   At this time, because the lower end of the second piston  83  and the contact portion  92 ′ provided at the lower end of the second coupling tube  82  contact not by the surfaces but by the circular linear portion at the edge of the protruding portion  1101  via the protruding portion  1101 , high liquidtightness can be accomplished even when manufacturing accuracy of the second piston  83  and the contact portion  92 ′ has deteriorated. 
   The above-mentioned valve mechanism  86  is used for closing the opening portion  41 ″ which communicating with the liquid storing portion  4  formed in the vicinity of the lower end of the second cylinder  23 ″ and the second cylinder  23 ″ when inside the second cylinder  23 ″ is pressurized and for opening the opening portion  41 ″ when inside the second cylinder  23 ″ is depressurized. 
     FIG. 18  shows an enlarged view of the valve mechanism  86 . 
   The valve mechanism  86  possesses a tapered portion  151  formed at the lower end of the second cylinder  23 ″ which functions as a valve seat, and a valve body  89 ″ possessing a tapered portion  152  having practically the same angle of gradient as that of the tapered portion  151 . It is preferred to produce the valve body  89 ″ by molding a flexible material. As a flexible material, for example, resin or silicone rubber can be used. 
   Additionally, at a portion at the tapered portion  151 of the second cylinder  23 ″, which contacts the valve body  89 ″, a circular protruding portion  103  is formed. Consequently, the second cylinder  23 ″ and the valve body  89 ″ contact each other via this circular protruding portion  103 . At this time, because the second cylinder  23 ″ and the valve body  89 ″ contact not by the surfaces but by the circular linear portion at the edge of the protruding portion  103  via the protruding portion  103 , high liquidtightness can be accomplished even when manufacturing accuracy of the second cylinder  23 ″ and the valve body  89 ″ has deteriorated. 
   At the lower end of the valve body  89 ″, a regulating portion  153  is provided. In the regulating portion  153 , a dividing groove is provided. By the action of the dividing groove, the regulating portion  153 , a dividing groove valve body  89 ″ can be pressed into the opening portion  41 ″ of the second cylinder  23 ″. Additionally, after being pressed into, coming off of the regulating portion from the opening portion  41 ″ can be prevented. 
   In the above-mentioned embodiment, at a portion at the tapered portion  151  of the second cylinder  23 ″, which contacts the valve body  89 ″, a circular protruding portion  103  is formed. As shown in  FIG. 19 , it is acceptable to form a circular protruding portion  1104  at a contact portion at the tapered portion  152  of the valve body  89 ″, which contacts the tapered portion  151  of the second cylinder  23 ″. 
   Liquid discharge motions of the above-mentioned liquid discharge container are described below. 
   In an initial position, as shown in  FIG. 12 , and  FIG. 13  and FIG. 16 ,by the action of a coil spring  24 , momentum is given to the first and the second coupling tubes  81 ′ and  82  in an upward direction, and the contact portion  92 ′ provided at the lower end of the second coupling tube  82  contacts the lower end of the second piston  83  via the protruding portion  1101 . Consequently, flow path leading to inside the first and the second coupling tubes  81 ′ and  82  from inside the second cylinder  23 ″ is closed. Additionally, by the empty weight of the valve body  89 ″, as shown in  FIG. 18 , the tapered portion  152  valve body  89 ″ contacts the tapered portion  151  of the second cylinder  23 ″ via the protruding portion  1101 , and the opening portion  41 ″ is closed. 
   In this position, if the pressing portion  12  at the nozzle head  2  is pressed, as shown in  FIG. 14 , the first and the second coupling tubes  81 ′ and  82  first descend relatively to the second piston  83 . By this motion, the contact portion  92 ′ provided at the lower end of the second coupling tube  82  separates from the lower end of the second piston  83 . Consequently, the flow path leading to inside the first and the second coupling tubes  81 ′ and  82  from inside the second cylinder  23 ″ via the opening portion  91  is formed. 
   If the pressing portion  12  at the nozzle head  2  is further pressed, as shown in  FIG. 17 , the lower end of the second coupling tube  81 ′ contacts the top surface of the second piston  83  via the protruding portion  1102 , and the second piston  83  and the first and the second coupling tubes  81 ′ and  82  descend all together. At this time, inside the second cylinder  23 ″ is pressurized, and as shown in  FIG. 18 , the opening portion  41 ″ is closed by the valve body  89 ″ contacting the second cylinder  23 ″ via the protruding portion  103 . Consequently, the pressurized liquid inside the second cylinder  23 ″ flows out to the nozzle head  2  via the opening  91  and the first and the second hollow coupling tubes  81 ′ and  82 , and is discharged from the discharge portion  11 . 
   After the second piston  83  descends until the lower limit of a stroke and if a pressure given to the nozzle head  2  is removed, by the action of the coil spring  24 , the first and the second coupling tubes  81 ′ and  82  ascend relatively to the second piston  83 . By this motion, as shown in  FIG. 15  and  FIG. 16 , the contact portion  92 ′ provided at the lower end of the second coupling tube  82  contacts the lower end of the second piston  82  via the protruding portion  1101 . Consequently, the flow path leading to inside the first and the second coupling tubes  81 ′ and  82  from inside the second cylinder  23 ″ is closed again. 
   After that, the nozzle head  2 , the first and the second coupling tubes  81 ′ and  82  and the second piston  83  ascend all together by the action of the coil spring  24 . At this time, because inside the second cylinder  23 ″ is depressurized, the opening portion  41 ″ is opened by the valve body  89 ″ separating from the protruding portion  103  formed at the second cylinder  23 ″, and the fluid flows into the second cylinder  23 ″ from the fluid storing portion  4 . When the second piston  83  moves to the upper limit of its elevating stroke, it stops to ascend. 
   By repeating the above-mentioned motions, discharging the fluid stored in the fluid storing portion  4  from the nozzle head  2  becomes possible. 
   In the above-mentioned embodiment, as shown in  FIG. 20(A) , as the protruding portions  1101 ,  1102 ,  103  and  1104 , those having a nearly V-shaped cross-sectional surface are used. As shown in  FIG. 20(B) , a protruding portion  201  having a nearly U-shaped cross-sectional surface also can be used. As shown in  FIG. 20(C) , a protruding portion  301  having configuration, in which a pair of circular protrusions  300  are arranged, also can be used. 
   Additionally, according to the forgoing valve mechanism of a liquid container, by forming a circular protruding portion at either of a valve seat or a valve body, and by contacting the valve seat and the valve body via the circular protruding portion, high liquidtightness can be accomplished while the manufacturing costs of valve mechanisms are kept low. 
   It will be understood by those of skill in the art that numerous and various modifications can be made without departing from the spirit of the present invention. Therefore, it should be clearly understood that the forms of the present invention are illustrative only and are not intended to limit the scope of the present invention.