Abstract:
A piston device comprises a sleeve, a casing pipe, a first piston, a resilient member, and a second piston. The sleeve includes at least one hole arranged at the periphery of its closed end. The casing pipe has at least a through hole arranged on a lateral side thereof proximate to its closed end and is sheathed and connected to the sleeve by a manner that the open end of the casing pipe is faced toward the closed end of the sleeve. The first piston is arranged to sheathe the casing pipe at a position proximate to the closed end of the casing pipe for selectively covering and exposing the through hole by a reciprocate movement. The resilient member is installed in side the sleeve at a position between the closed end of the sleeve and the first piston while ensheathing the casing pipe therethrough. The second piston is arranged to sheathe the sleeve at a position proximate to its open end. Moreover, by combining the piston device with a container containing fluid and gas, a fluid/gas drawing apparatus can be formed, and, by combining the fluid/gas drawing apparatus with a nozzle, a foam producing apparatus capable of producing thick foams can be formed.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a piston device, and more particularly, to a piston device capable of having two pistons separately installed in two pipes of different diameters that contain fluids for providing alternate back-and-forth movements to draw gases and liquids and a nozzle for mixing the fluids is combined with the piston device to produce foams, and the invention also relates to a fluid drawing apparatus and a foam producing apparatus that use such piston device. 
   BACKGROUND OF THE INVENTION 
   As the standard of our life advances, the methods of using daily commodities such as beauty treatment kits, and personal sanitary and bath products indispensable to our life are improved according to the advancement of related technologies. For example, shampoo has evolved from shampoo powder to bottled liquid shampoo, and users just need to gently press the bottle to draw liquid shampoo. The major core of these products resides on the apparatus of drawing liquid shampoo or hair gel. This type of pump drawing apparatus simply requires users to press a pull handle or a press handle to draw the liquid from a can or a bottle and obtain the desired result (such as sprays, foams, or liquid discharges). 
   Referring to  FIG. 1  for the schematic view of a drawing structure of a prior art sprayer, the drawing structure  1  includes a casing pipe  12  coupled to the bottom of a nozzle  11 , and the casing pipe  12  includes a drawing pipe  13 , and the bottom of the drawing pipe  13  is coupled to a conical cover  14 . The bottom of the conical cover  14  allows a pressing rod  15  to pass through, and the rear end of the pressing rod  15  presses against an end of a spring  16 , and another end of the spring  16  has a ball  17 , and a containing pipe  18  accommodates the drawing pipe  13 , conical cover  14 , pressing rod  15 , spring  16 , and ball  17  vertically and sequentially in the pipe, and the bottom of the containing pipe  18  includes a sucking pipe  19 , and the whole drawing structure  1  is placed in a liquid can or bottle for drawing liquids. 
   The related drawing apparatuses for drawing liquid from a bottle have been disclosed in R.O.C. Pat. Application Nos. 094202158 and 088205688. The drawing apparatuses as disclosed in forgoing patented technology can only draw a liquid, but cannot simultaneously draw a liquid and a gas. In certain occasions that require the use of foams such as disk washing or hair shampooing, the foregoing drawing apparatuses are generally used for drawing detergent or shampoo, and users produce foams by rubbing the detergent or shampoo with hands. However, such arrangement usually cannot control the consuming quantity of detergent or shampoo. Particularly, excessive detergent may remain on kitchenware, if the kitchenware is not rinsed thoroughly, and finally may hurt human bodies. The same situation applies to shampoo, and the shampoo remained on our scalp may cause damages to our scalp. 
   In summation to the description above, a piston device and a fluid drawing apparatus and a foam producing apparatus using such piston device are required to provide the functions of drawing a liquid and a gas as well as appropriately producing foams easily, so as to overcome the shortcomings of the prior art. 
   SUMMARY OF THE INVENTION 
   The primary objective of the present invention is to provide a piston device and a fluid drawing apparatus and a foam producing apparatus using such piston device, and the piston device comprises two pistons installed in two pipes having different diameters and containing fluids for alternate back-and-forth movements, so as to achieve the effect of discharging gases and liquids from the pipe. 
   The secondary objective of the present invention is to provide a piston device and a fluid drawing apparatus and a foam producing apparatus using such piston device, and the resilience of a resilient member drives two pistons to move back and forth in the pipes of different diameters, such that vacuum suctions can be produced during the return path of the pistons to achieve the effects of drawing a liquid from a can and drawing an external air. 
   Another objective of the present invention is to provide a piston device and a fluid drawing apparatus and a foam producing apparatus using such piston device, and the piston device comprises two pistons installed in two pipes of different diameters and containing fluids for alternate back-and-forth movements to discharge gases and liquids, and the fluids pass through a nozzle for mixing the fluids to achieve the effect of producing foams. 
   To achieve the foregoing objectives, a piston device of the invention comprises: a sleeve, having at least one hole disposed around the periphery of a closed end thereof; a casing pipe, having at least one through hole arranged on a lateral side thereof proximate to its closed end and being sheathed and connected to the sleeve by a manner that the open end of the casing pipe is faced toward the closed end of the sleeve; a first piston, being arranged to ensheathe the casing pipe therethrough at a position proximate to the closed end of the casing pipe for selectively covering and exposing the through hole by a reciprocate movement; a resilient member, being installed in side the sleeve at a position between the closed end of the sleeve and the first piston while ensheathing the casing pipe therethrough; and a second piston, being arranged to ensheathe the sleeve at a position proximate to the open end of the sleeve. 
   Preferably, a closed end of the sleeve is coupled to a hollow piping, and an open end of the hollow piping is interconnected to a closed end of the sleeve, and another open end of the hollow piping is disposed inside the sleeve. The hollow piping further comprises a groove disposed at an open side of the sleeve for accommodating an open end of the casing pipe. One end of the resilient member presses against a pipe-opening wall of the hollow piping while the other end presses against the first piston. 
   Preferably, the hollow piping is coupled to an end of the casing pipe and the external wall of the casing pipe has screw threads mutually engaged to the hollow piping. 
   Preferably, the sidewall of the sleeve further includes a first circular blocking member, and the open end of the sleeve includes the second circular blocking member such that the second piston can move back and forth between the first circular blocking member and the second circular blocking member, wherein the second piston includes a plurality of protruding ribs disposed on a wall surface corresponding to the sidewall of the sleeve for forming a plurality of partition spaces between the second piston and the sleeve. 
   To achieve the foregoing objectives, a fluid drawing apparatus of the present invention comprises: a sleeve, having at least one hole disposed around the periphery of a closed end thereof; a casing pipe, having at least one through hole arranged on a lateral side thereof proximate to its closed end and being sheathed and connected to the sleeve by a manner that the open end of the casing pipe is faced toward the closed end of the sleeve; a first piston, being arranged to ensheathe the casing pipe therethrough at a position proximate to the closed end of the casing pipe for selectively covering and exposing the through hole by a reciprocate movement; a resilient member, being installed in side the sleeve at a position between the closed end of the sleeve and the first piston while ensheathing the casing pipe therethrough; a second piston, being sheathed along a sidewall proximate to the open end of the sleeve; a casing, including a first space and a second space, and the first space maintaining airtight with the first piston while the second space maintaining airtight with the second piston; and a second resilient member, installed in the casing wherein one end of the second resilient member presses against the second piston while the other end of the second resilient member presses against the bottom of the casing. 
   Preferably, the casing further comprises an external pipe for accommodating the second piston, and the internal wall of the external pipe maintains airtight with the second piston, and an internal pipe is installed in the external pipe, and an open end of the internal pipe is interconnected to a closed end of the external pipe, and the internal wall of the internal pipe maintains airtight with the first piston, and the diameter of the internal pipe is smaller than the diameter of the sleeve. An area between the external pipe and the internal pipe is the second space, and a space inside the internal pipe is the first space. The internal pipe further includes a check valve disposed at an end interconnected to the external pipe. 
   Preferably, the second resilient member is sheathed onto the internal pipe. 
   Preferably, the check valve further comprises: at least one blocking member disposed on the internal wall of the internal pipe; a hollow flared member installed onto the internal pipe interconnected to an end of the external pipe; and a sphere disposed between the blocking member and the hollow flared member, and the diameter of the sphere falls in the range of the maximum and minimum diameters of the hollow flared member. The flared member is further coupled to a sucking pipe. 
   To achieve the foregoing objective, a foam producing apparatus of the present invention comprises: a sleeve, having at least one hole disposed around the periphery of a closed end thereof; a casing pipe, having at least one through hole arranged on a lateral side thereof proximate to its closed end and being sheathed and connected to the sleeve by a manner that the open end of the casing pipe is faced toward the closed end of the sleeve; a first piston, being arranged to ensheathe the casing pipe therethrough at a position proximate to the closed end of the casing pipe for selectively covering and exposing the through hole by a reciprocate movement; a resilient member, being installed in side the sleeve at a position between the closed end of the sleeve and the first piston while ensheathing the casing pipe therethrough; a second piston, being sheathed along a sidewall proximate to the open end of the sleeve; a casing, including a first space and a second space, and the first space maintaining airtight with the first piston while the second space maintaining airtight with the second piston; a second resilient member, installed in the casing wherein one end of the second resilient member presses against the second piston while the other end of the second resilient member presses against the bottom of the casing; and a fluid/gas mixing nozzle, coupled and interconnected to the sleeve. 
   Preferably, the fluid/gas mixing nozzle further comprises: a nozzle having an accommodating space; and a valve installed in the accommodating space, and a side of the valve having a fluid mixing space interconnected to the casing pipe and another side having a valve plate proximate to the hole, and a valve having a circular post proximate to the surface of the valve plate, and a wall surface of the circular post having an air hole interconnected to the fluid mixing space, wherein a first net member is installed between the circular post and the fluid mixing space, and a second net member is installed between the nozzle and the fluid mixing space. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view of a prior art fluid drawing apparatus; 
       FIG. 2A  is an exploded view of a piston device according to a preferred embodiment of the present invention; 
       FIG. 2B  is a cross-sectional view of a piston device according to a preferred embodiment of the present invention; 
       FIG. 3  is a cross-sectional view of a fluid/gas drawing apparatus according to a preferred embodiment of the present invention; 
       FIG. 4  is a cross-sectional view of a foam producing apparatus according to a preferred embodiment of the present invention; 
       FIG. 5  is a schematic view of a foam bottle comprised of a foam producing apparatus according to a preferred embodiment of the present invention; 
       FIG. 6A  is a schematic view of the movements of a foam producing apparatus being compressed to produce foams according to the present invention; and 
       FIG. 6B  is a schematic view of the return path of a foam producing apparatus according to the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   To make it easier for our examiner to understand the objective of the invention, its structure, innovative features, and performance, we use a preferred embodiment together with the attached drawings for the detailed description of the invention. Only some embodiments of the present invention have been illustrated in the drawings, but it should be pointed out that many other modifications are conceivable within the scope of the following claims. 
   Referring to  FIGS. 2A and 2B  for the exploded view and the cross-sectional view of a piston device according to a preferred embodiment of the present invention respectively. The piston device  2   a  comprises a sleeve  21 , a casing pipe  23 , a first resilient member  22 , a first piston  24 , and a second piston  25 . The sleeve  21  is a hollow cylindrical body, wherein one side of the sleeve  21  is an opening, and the other side is a closed surface. The rim of the closed surface includes a plurality of holes  212  interconnected to the hollow area inside the sleeve  21 . The quantity of holes  212  depends on actual needs and basically there just at least one hole is enough for requirement. In this preferred embodiment, the number of holes  212  is more than one. In  FIG. 2B , the central area of the closed surface of the sleeve  21  has a hollow piping  210 , and one opening of the channel  211  of the hollow piping  210  protrudes from the closed surface of the sleeve  21 , while the other opening of the channel  211  at the end of the hollow piping  210  is disposed inside the hollow area of the sleeve  21 . The opening of hollow piping  210  inside the sleeve  21  has a groove, and the sidewall of the groove has a screw thread for the fixing purpose. 
   The casing pipe  23  is a hollow pipe, and one side of the casing pipe  23  is a closed surface, while the other side is an open surface. The casing pipe  23 , passing through the first piston  24  and the first resilient member  22 , connects with the hollow piping  210 . A portion of the external wall of the casing pipe  23  proximate to the open end has a screw thread  232  that can be engaged with the screw thread on the internal wall of the groove of the hollow piping  210 , so that the casing pipe  23  can be fixed in the hollow piping  210 . The hollow channel inside the casing pipe  23  and the hollow piping  210  both constitute a channel  233  for fluid running. As to the ways for fixing the casing pipe  23  and the hollow piping  210 , there are many different ways to achieve, and it should not be limited to the way disclosed in this preferred embodiment only. A lateral side of the casing pipe  23  proximate to the closed surface includes two corresponding through holes  231  (only one through hole  231  is shown in the figure), and the through hole  231  is interconnected to the channel  233  inside the casing pipe  23 . 
   An end of the first resilient member  22  presses against the external wall of the opening of the hollow piping  210  while the other end presses against the first piston  24 . When the first resilient member  22  is in its initial state, the first piston  24  will cover the through hole  231  so as to prevent the through hole  231  from communicating with the external area. If an external force is applied to the first piston  24  to compress the first resilient member  22 , then the through hole  231  will be exposed so that fluid in the external area can flow to the channel  233  through the through hole  231 . Therefore, the external force and a restoring force of the first resilient member  22  can reciprocate the first piston  24  along the casing pipe  23  for selectively covering and exposing the through hole  231 . 
   A hollow area of the second piston  25  ensheathes the sidewall  215  of the sleeve  21 , and, as shown in  FIG. 2A , the hollow area of the second piston  25  includes a plurality of protruding ribs  252  disposed on a wall surface corresponding to the sidewall  215  of the sleeve  21  for forming a plurality of partition spaces  251  between the hollow area of the second piston  25  and the sidewall  215  of the sleeve. To allow and restrict the second piston  25  to slide along the sidewall  215  of the sleeve  21 , the sidewall  215  of the sleeve  21  further comprises a first circular blocking member  213 ; meanwhile, the opening of sleeve  21  uses a latch member  214  to latch a latch member  261  of the second circular blocking member  26 , so that the second piston  25  can be constrained to slide between the first and second circular blocking member  213 ,  26 . 
   The first circular blocking member  213  comes with an arc-shape design. If the first circular blocking member  213  contacts against the second piston  25 , the partition space  251  will be airtight completely at the side which the second piston  25  contact with the first circular blocking member  213 . One purpose of the second circular blocking member  26  is to prevent the second piston  25  from being separated from the sleeve  21 . Besides providing a partition space, the plurality of protruding ribs  252  also allows a one-dimensional steady sliding movement for the second piston  25  along the sleeve  21 . Of course, the protruding ribs  252  adopted in this preferred embodiment are not limited to such arrangement. For example, removing the protruding ribs  252  or implementing the protruding ribs  252  by other methods, such as disposing the protruding ribs on the sidewall  215  other than the second piston  25  alternatively, are also covered in the scope of the patent claims of this invention. 
   Referring to  FIG. 3  for the schematic view of a fluid/gas drawing apparatus according to a preferred embodiment of the present invention, the piston device  2   a  as shown in  FIG. 2A  is coupled to a casing  27  to form a fluid/gas drawing apparatus  2   b  capable of drawing liquids and gases. The casing  27  includes an external pipe  271  and an internal pipe  272 . The internal wall of the external pipe  271  maintains airtight with the second piston  25 , so that the second piston  25  can reciprocate along the internal wall of the external pipe  271 . The internal pipe  272 , disposed inside the external pipe  271 , interconnects to the external pipe  271  to communicate with the outside, and a second resilient member  273  is arranged around the external wall of the internal pipe  272 . The internal wall of the internal pipe  272  maintains airtight with the first piston  24 . 
   The diameter of the internal pipe  272  is smaller than the diameter of the sleeve  21 , so that the second piston  25  can move back and forth along the internal wall of the external pipe  271  smoothly. One side of the second circular blocking member  26  presses against the second resilient member  273 , and the second resilient member  273  provides a restoring force required for the back-and-forth movements of the second piston  25 . The space between the internal wall of the external pipe  271  and the external wall of the internal pipe  272  is a gas space  2711 , and the space inside the internal pipe  272  is a liquid space  2721 . 
   The exterior at the bottom of the casing  27  further comprises a check valve, comprising a hollow flared member  274  communicates with the end of the internal pipe  272 . The hollow flared member  274  contains a steel ball  275 . To prevent the steel ball  275  falling out from the hollow flared member, at least one blocking member  276  is disposed at the internal wall of the internal pipe  272  proximate near to the opening of the hollow flared member for constraining the steel ball  275  in the hollow flared member  274 . The diameter of the steel ball  275  falls in the range of the maximum and minimum diameters of the hollow flared member  274 . The opening of the flared member  274  having maximum diameter is interconnected to the internal pipe  272 , and the opening of the flared member  274  having minimum diameter is coupled to a sucking pipe  277 . 
   Referring to  FIG. 4  for the cross-sectional view of a foam producing apparatus according to a preferred embodiment of the present invention, the fluid drawing apparatus  2   b  as shown in  FIG. 3  is coupled to a fluid/gas mixing nozzle  28  to form a foam producing apparatus  2   c . The fluid/gas mixing nozzle  28  includes a nozzle  281  and a valve  282 . The nozzle  281  includes an accommodating space  2811  and the nozzle  281  is connected onto the sleeve  21 . The valve  282  is installed in the accommodating space  2811 , and one side of the valve  282  has a fluid mixing space  2821  interconnected to the casing pipe  23  and the other side has a valve membrane  2822  adjacent to the hole  212 . The valve  282  proximate to the lateral surface of the valve membrane  2822  has a circular post  284  whose lateral surface has air holes  2841  interconnected to the fluid mixing space  2821 , and which is interconnected to the hollow piping  210 . Therefore, a liquid passing from the internal pipe  272  through the casing pipe  23  and the hollow piping  210  to the circular post  284  and entering into the fluid mixing space  2821  can mix with a gas entering from the air hole  2841  to the fluid mixing space  2821 . To achieve a better foam producing effect, a first net member  2823  is installed between the circular post  284  and the fluid mixing space  2821 , and a second net member  283  is installed between the nozzle  281  and the fluid mixing space  2821 . 
   Referring to  FIG. 5  for the schematic view of a foam bottle comprised of a foam producing apparatus according to a preferred embodiment of the present invention. A foam bottle  2   d  is formed by combining a can  20  with the foam producing apparatus  2   c  wherein a lid  29  is adopted to fix the foam producing apparatus  2   c  and the can  20 . Referring to  FIG. 6A  which is the schematic view of the movements of a foam producing apparatus being compressed to produce foams according to the present invention. A user can apply a pressure  90  onto the fluid/gas mixing nozzle  28  to produce the foam. The foam producing process is expressed in the following two actions: one is drawing a gas and the other is drawing a liquid. When the user applies a pressure, the fluid/gas mixing nozzle  28  will press the sleeve  21  to move downward. As a result, the sleeve  21  will drive the second piston  25  to move downward. Since the second piston  25  keeps airtight with the internal wall of the external pipe  271 , the gas in the gas space  2711  will exert an acting force onto the second piston  25  during the downward process. Since the second piston  25  is capable of sliding along the sidewall  215  of the sleeve  21 , therefore the second piston  25  will slide upward and press against the first circular blocking member  213  due to the acting force generated from gas inside the gas space  2711 . 
   Although a partition space (not shown in the figure) is disposed between the second piston  25  and the sidewall of the sleeve  21 , the gas in the gas space  2711  will not leak from the partition space due to the second piston  25  contacting with the first circular blocking member  213  airtightly. Since the diameter of the sleeve  21  is larger than the diameter of the internal pipe  272 , during the second piston  25  moves downward in the external pipe  271 , a gap (as shown in an area indicated by a solid-line arrow), which is between the sleeve  21  and the internal pipe  272 , will be produced, and the gas compressed by the second piston  25  will be pushed and discharged from the gap between the internal wall of the sleeve  21  and the external wall of the internal pipe  272 . With the further continuous movement downward of the second piston  25 , the pressure will push the gas from a space  216  inside the sleeve  21  through the hole  212  and pass through the valve membrane  2822 , and then the gas will pass through the air hole  2841  and the first net member  2823  into the fluid mixing space  2821 . In the figure, a solid-line arrow indicates the moving direction of the gas. 
   The way of drawing a liquid  4  will be described as follows. If a user presses the fluid/gas mixing nozzle  28 , the fluid/gas mixing nozzle  28  will drive the sleeve  21  to move downward, and thus the sleeve  21  will drive the first piston  24  to move downward to push the liquid  4  in the liquid space  2721  of the internal pipe  272 . Due to the existence of the steel ball  275 , the liquid  4  will not flow back into the can  20 ; instead the liquid  4  reacts on the first piston  24 . If such reacting force generated from the liquid  4  is greater than the resilience of the first resilient member  22 , the first piston  24  will move upward by the pressing of the liquid  4 . Once the first piston  24  moves upward, the through hole  231  is exposed so that the liquid  4  inside the liquid space  2721  is capable of flowing into the channel  233  of the casing pipe  23  via the through hole  231  and moves upward to pass through the channel  211  of the hollow piping, the first net member  2823  subsequently and, finally, into the fluid mixing space  2821 . The gas  5  and the liquid  4  in the fluid mixing space  2821  are pushed by the pressure to pass the second net member  283  to produce thick foams  92  and the foams  92  are discharged from the nozzle  281 . 
   Referring to  FIG. 6B  for the schematic view of the return path of a foam producing apparatus according to the present invention, the foam will be produced if a user presses the fluid/gas mixing nozzle  28  all the way down to the bottom. The resilience of the second resilient member  273  will push the second piston  25  and the sleeve  21  to move upward, after the user releases the fluid/gas mixing nozzle  28 . This stage during the upward movement also includes two processes, which are a gas incoming process and a liquid incoming process. For the gas incoming process, the gas in the gas space  2711  is discharged in the previous compressing process, and thus the pressure in the gas space  2711  will be a vacuum state. Since the pressure in the gas space  2711  is small and the pressure of the gas in the external space  279  between the lid  29  and the second piston  25  is the atmospheric pressure, therefore the gas in the external space  279  will produce a pushing force to push the second piston  25  to move downward, so that the second piston  25  presses against the second circular blocking member  26  so as to make the partition space  251  communicate with the external space  279 . 
   The pressure of the gas in the gas space  2711  is smaller than that in the external space  279  during upward movement, and thus the gas in the external space  279  will be sucked into the gas space  2711  in the direction indicated by a solid line in  FIG. 6B . After the second resilient member  273  recover to its initial state, the gas space  2711  is filled up with gas again and gets ready for the next compressing process. Meanwhile, during the upward movement, the valve membrane  2822  in the fluid/gas mixing nozzle  28  becomes a one-way check valve to prevent the gas  5  entering from the opening of the nozzle  281  and also prevent the liquid in the fluid mixing space  2821  from flowing back into the gas space  2711 , which will affect the compressing effect. 
   As to the liquid incoming process, the liquid in the liquid space  2721  has been consumed in previous compression. During the returning process, the liquid space  2721  is in a vacuum state, which means that the first piston  24  is no longer exerted by the liquid inside the liquid space, so that the first piston  24  will resume its original position under the action of the restoring force of the first resilient member  22 . The liquid space  2721  will be in a vacuum state to generate a sucking force to draw the liquid  4  in the can  20  from the sucking pipe  277  to the liquid space  2721  as indicated by the dotted line in the figure. After the second resilient member  273  and the first resilient member  22  resumes its original uncompressed state, the liquid space  2721  will be filled up with liquid for the next compressing process. 
   In summation to the description above, the assembly of the present invention has a fluid drawing capability and produces thick foams for the users and thus satisfying the requirements of the industry and enhancing the competitiveness of the industry. The present invention definitely complies with the patent application requirements, and thus is submitted to the Patent and Trademark Office for review and granting of the commensurate patent rights.