Abstract:
A foam spray head assembly includes a head, a first piston unit, a valve unit, a link, a second piston unit, a cylinder, a resilient member and a resilient valve. The valve unit is directly connected to the head to allow the valve unit to receive the pressing force of the head to quickly respond in the form of reciprocating motion. The parts made of metal such as the spring is isolated from the liquid to ensure that the liquid is not affected by the metal.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to a spray head assembly, and more particularly, to a foam spray head assembly. 
     (2) Description of the Prior Art 
     A conventional spray head assembly  100  is shown in  FIG. 5  and generally includes a head  101  with a nozzle  101   a  and a mounting part  102  is connected to the head  101 . The mounting part  102  is connected to a suction tube  103  which has a cone-shaped member  104  connected thereto. A mount tube  105  is connected to the cone-shaped member  104  and has two holes  105   a  which are covered by the cone-shaped member  104 . A spring  106  is connected to the mount tube  105  and a bead  107  is biased by the spring  106 . A reception tube  108  accommodates the suction tube  103 , the cone-shaped member  104 , the mount tube  105 , the spring  106  and the bead  107  therein, and a hose  109  is connected to the reception tube  108 . 
     When using the assembly, the head  101  is pushed to force the air in the bottle to escape from the nozzle  101  so that a low pressure is formed in the head  101  to suck the liquid in the bottle via the hose  109  into the reception tube  108 . The mount tube  105  is applied byte force of the spring  106  to push the bead  107  to seal the opening of the reception tube  108  and gap is defined between the mount tube  105  and the cone-shaped member  104 . Therefore, the liquid in the reception tube  108  flows into the mount tube  105  via the holes  105   a . The liquid is then sucked by the suction tube  103  and ejected from the nozzle  101   a  of the head  101 . When releasing the head  101 , the liquid in the reception tube  108  flows back into the bottle. 
     However, the conventional spray head assembly is designed to suck liquid and cannot suck the liquid together with air which makes the liquid into foam. Generally, the users spray the liquid such as shampoo from the bottle and then scrub the hands to make the shampoo into foam. The amount that the shampoo is sprayed cannot be easily controlled so that the foam is either too much or not enough. This is inconvenient for the users. Besides, the spring  106  and the bead  107  are made by metal which are in contact with the liquid in the reception tube  108  and the liquid may have chemical action with the metal and may be harmful to the users. 
     The present invention intends to provide a spray head assembly that improves all of the shortcomings of the conventional spray head assembly. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a spray head assembly and comprises a head having a nozzle and a space defined therein. A filter tube is located in the space. A first piston unit has a top opening and a bottom opening, and a sealing member is located in the bottom opening. A valve unit has a first valve and a second valve, wherein the first valve has a first end connected to the first piston unit and a second end of the first valve is connected to the filter tube and the head. The second valve has a first end connected to the first valve and is mounted to the first piston unit. The second valve has a flange which is separated from the sealing member to form an inlet path when the first valve moves toward the second valve. 
     A link has a tubular portion which extends through the second valve. Multiple grooves are defined axially in an outer surface of the tubular portion. A stop flange extends radially from an end of the tubular portion. A second piston unit is slidably mounted to the link and movable along the link to seal the grooves or to allow the grooves to be exposed. A cylinder has a top chamber and a bottom chamber, wherein the bottom chamber accommodates the second piston unit and the link. A through hole is defined through the bottom chamber. A resilient member is located in the top chamber and contacts between the second valve and an inner end of the top chamber. A resilient valve is a spiral valve and located in the bottom chamber of the cylinder. The resilient valve is movable to seal or open the through hole. A positioning member is mounted to the bottle to connect the foam spray head assembly to the bottle. 
     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view to show the foam spray head assembly of the present invention; 
         FIG. 2  is a cross sectional view of the foam spray head assembly of the present invention; 
         FIG. 3  is a cross sectional view to show one of the operated status of the foam spray head assembly of the present invention; 
         FIG. 4  is a cross sectional view to show another one of the operated status of the foam spray head assembly of the present invention, and 
         FIG. 5  is an exploded view to show a conventional spray head assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 and 2 , the foam spray head assembly  10  of the present invention comprises a head  1  having a nozzle  11  connected thereto and a space  12  is defined in the head  1 . A filter tube  13  is located in the space  12 . Two ends of the filter tube  13  are respectively mounted with a first filter  131  and a second filter  132 . The first filter  131  has fine holes and the second filter  132  has large holes. 
     A first piston unit  2  is a hollow part and has a top opening  21  and a bottom opening  22  in two ends thereof. A sealing member  221  located in the bottom opening  22  and has a tapered central tube which resiliently mounts to the first valve  31  to seal the top chamber  61  of the cylinder  6 . A valve unit  3  has a first valve  31  and a second valve  32 , wherein the first valve  31  has a first end connected to the first piston unit  2  and a second end of the first valve  31  is connected to the filter tube  13  and the head  1 . The second valve  32  has a first end connected to the first valve  31  and is mounted to the first piston unit  2 . The second valve  32  has a mount tube  321  and a hollow extension tube  322  formed on two opposite ends thereof. The mount tube  321  is connected to the first valve  31  and an outgoing path  33  is defined between the mount tube  321  and the first valve  31 . The mount tube  321  of the second valve  32  has a mixing space  35  defined therein. The second valve  32  has a flange  323  which is separated from the sealing member  221  to form an intake path  34  when the first valve  31  moves toward the second valve  32 . 
     A link  4  has a tubular portion  41  which extends through the second valve  32 , and multiple grooves  411  are defined axially in an outer surface of the tubular portion  41 . A stop flange  42  extends radially from an end of the tubular portion  41 . A second piston unit  5  is slidably mounted to the link  4  and movable along the link  4  to seal the grooves  411  or to allow the grooves  411  to be exposed; 
     A cylinder  6  whose outer diameter is gradually reduced and has a top chamber  61  and a bottom chamber  62 . An inner diameter of the top chamber  61  is larger than that of the bottom chamber  62 . The bottom chamber  62  accommodates the second piston unit  5  and the link  4 . A through hole  621  is defined through the bottom chamber  62 . The bottom chamber  62  of the cylinder  6  has a connection port  622  which includes a suction tube  63  connected thereto which extends into the bottle  20 . A resilient member  7  is located in the top chamber  61  of the cylinder  6  and contacts between the second valve  32  and an inner end of the top chamber  61  of the cylinder  6 . 
     A resilient valve  8  is a spiral valve and located in the bottom chamber  62  of the cylinder  6 , the resilient valve  8  movable to seal or open the through hole  621 . The resilient valve  8  includes a first end  81  and a second end  82 , the first end  81  has a passage  811  and the second end  82  seals the through hole  621 . A hollow resilient portion  83  is connected between the first and second ends  81 ,  82  so that the through hole  621  can be opened and closed when the resilient valve  8  is moved reciprocally. After all of the parts such as the head  1 , the first piston unit  2 , the valve unit  3 , the link  4 , the second piston unit  5 , the cylinder  6 , the resilient member  7  and the resilient valve  8  are installed and positioned, a positioning member  9  is connected to the bottle  20  and has a threaded portion  91  which is connected with the head  1  to connect the spray head assembly to the bottle  20 . 
     The first valve  31  includes multiple inlets  311  defined in an inner periphery thereof and an outside of the top opening  21  of the first piston unit  2  seals the inlets  311  when the first valve  31  moves toward the second valve  32 . The space  12  in the head  1  includes a groove portion  121  defined in an inner periphery thereof and the first valve  31  includes a protrusion portion  312  on an outside thereof. The protrusion portion  312  is engaged with the groove portion  121  to connect the first valve  31  to the head  1 . 
     As shown in  FIG. 3 , when the head  1  is pressed downward, the first and second valves  31 ,  32  are lowered in sequence so that the link  4  is lowered to reduce the volume of the bottom chamber  62 . Due to the hydraulic pressure, the second end  82  of the resilient valve  8  is lowered to seal the through hole  621  of the cylinder  6  to seal the bottom chamber  62 . Therefore, the stop flange  42  of the link  4  is separated from the second piston unit  5 , and the grooves  411  of the link  4  are exposed. The liquid in the bottom chamber  62  enters into the mixing space  35  via the second valve  32  by the high pressure. In the meanwhile, the flange  323  of the second valve  32  is gradually separated from the sealing member  221  to form an intake path  34 . The inlet  311  of the first valve  31  is gradually in contact with the top opening  21  of the first piston unit  2  to seal the inlet  311 . The first piston unit  2  gradually reduces the volume of the top chamber  61  and the air in the top chamber  61  flows into the outgoing path  33  via the intake path  34 , and then enters into the mixing space  35  of the second valve  32 . The air and the liquid are mixed in the mixing space  35  and then the mixture passes through the filter tube  13  to generate foam which is ejected from the nozzle  11 . During the pressing action to the head  1 , the valve unit  3  directly receives the pressure from the head  1  so as to quickly respond. 
       FIG. 4  shows that when releasing the head  1 , by the force of the resilient member  7 , the first and second valves  3 , 1   32  and the link  4  are pushed upward, and the inlet  311  of the first valve  31  is separated from the top opening  21  of the first piston unit  2  such that the inlet  311  gradually opened. In the meanwhile, the flange  323  of the second valve  32  seals the top chamber  61 . Along with the upward movement of the first piston unit  2   y  the second valve  32 , the volume of the top chamber  61  increases and the air outside is sucked into the top chamber  61  via the inlet  311 . The upward movement of the second valve  32  pushes the link  4  upward and the stop flange  42  of the link  4  seals the second piston unit  5 , such that the pressure in the bottom chamber  62  is lower than the outside pressure. The liquid can pushes the second end  82  and is sucked into the bottom chamber  62  via the passage  811  of the resilient valve  8 , and ready for the next pressing action. 
     The sealing member  221  seals the first valve  31  so that the top chamber  61  of the cylinder  6  is closed, and this improves the shortcoming of leakage of the conventional foam spray head assembly. 
     While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.