Patent Publication Number: US-2010111735-A1

Title: Foam Pump

Description:
CROSS REFERENCE TO THE RELATED PATENT APPLICATION 
     The present application claims the priority of the Chinese patent application No. 200820167006.8, which application is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     This invention relates to a kind of foam pump. 
     BACKGROUND OF THE INVENTION 
     Existing foam pumps have large screw bases and sizes, for instance, the Chinese patent of the applicant under the publication number of CN 201073625 (patent number: CN200720113219.8) authorized on Jun. 18, 2008 disclosed a kind of foam pump comprising the pump body, the big piston, the big piston rod, the small piston, the small piston rod, the head cap and the foam screen featured by that an one-way valve connected with the air cavity in the big piston is provided in said big piston rod, the main body of said one-way valve adopts sleeve-shaped valve leaves made of elastic material which are provided with staged surfaces for installation on the fixing base of said big piston rod, said valve leaf adopting tapered sealing surface with ascending diameter on the upper part for tight engagement with the connecting hole on said big piston, which connects the air-liquid mixing cavity in said big piston rod with the air cavity in said big piston. Foam pump of this structure adopts separated cap and bump body, thus the screw base cannot be too small, leading to large size of the pump. More over, the spring is provided outside of the small piston rod and inside the big piston rod, which makes the spring subject to contact with the liquid, which increases the possibility of secondary contamination of the liquid. 
     SUMMARY OF THE PATENT 
     The technical issue for this invention to solve is to provide a kind of foam pump with more compact and reasonable structure and better foaming effect while maintaining the advantage of fine one-way air inlet effect. 
     The technical solution of this invention to solve the technical issue above is: A foam pump, comprising a pump body, a big cover, a big piston, an small piston, piston rod, head cap and the foam screen; an one-way valve being provided in said piston rod connected with said air cavity of pump body, said one-way valve adopting sleeve-shaped valve leaves made of elastic materials, which are provided with staged surfaces to be installed inside said piston rod, said valve leaves further adopting sealing valve with ascending diameter becoming bigger gradually and tapered cavity on the upper part for tight engagement with the connecting hole on said piston rod, which connects the air-liquid mixing cavity in said big piston rod with the air cavity in said big piston; said piston rod being connected with said head cap from the inside; said foam pump further featured by that: said pump body is at the upper part, said big cover is at the lower part, said pump body being integrated with said big cover, said head cap being integrated with the lower big piston; a sealing ring of elastic materials being provided between said big piston and the inner wall of said pump body for tight engagement, which forms an one-way valve structure. 
     As a further improvement, said big cover is provided with an air hole for connection with the outside, said air hole being connected with the outside via an one-way valve inside said big cover, which facilitates the air to enter the atomizer connected with the thread of the big cover to extrude the liquid and improve the foaming effect. 
     Said one-way valve adopts the tight engagement of elastic valve and air holes, which is a simple structure. 
     Said one-way valve structure is to form a circular groove along the circumference of said big piston, allowing said sealing ring to slide up and down inside said groove, which is provided with an air inlets for connection with the outside on the inner lower wall and the bottom. With this structure, air supplementation to the air cavity from the outside can be realized. 
     As a further improvement, a circular groove is formed on the lower part of said pump body, said piston rod is provided with a shoulder, said piston rod is sleeved with a spring, which is supported between said circular groove and said shoulder, which effectively separates said spring from the liquid and prevents the liquid from secondary contamination and thus keeps the product more hygienic. 
     Said pump body is sleeved in a shield, the big piston on said head cap is located inside the shield cam ring, which sets the upper limit of said big piston, said shield and said head cap being engaged flexibly to facilitate air from the outside to enter the air cavity for air supplementation. 
     Compared with existing technologies, this invention has the advantages as follows: makes the pump body and the big cover integrated, thus the air cavity can be enlarged, the working pressure of the foam pump can be improved with the big cover of the same size, and the foaming effect of the foam pump can be enhanced; it further integrates the head cap with said big piston, providing sealing ring out of elastic material between the big piston and the pump body, which simplifies the structure of the big piston, in the meanwhile, the pump body itself is used as the piston cavity case of the big piston, there&#39;s no need to provide separate piston cavity case, which further simplified the structure of the foam pump and makes the internal structure of the foam pump more compact. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is the structural diagram of the embodiment of this invention (normal condition); 
         FIG. 2  is the structural diagram of the embodiment of this invention (extruded); 
         FIG. 3  the 3D explode view of the embodiment of this invention. 
     
    
    
     DETAIL DESCRIPTION OF THE INVENTION 
     Detailed description of this invention will now be described with reference to the drawings. 
     The embodiment as shown in  FIGS. 1-3  is a preferred embodiment of this invention. 
     A foam pump, comprising main parts of the pump body  1 , big cover  2 , big piston  3 , small piston  4 , piston rod  5 , spring  13 , head cap  6  and the foam screen  7 ; said pump body  1  and big cover  2  being formed into a integral structure, the pump body  1  being the upper part, the big cover  2  being the lower part, the upper part being corresponding to the pump body in the former patent, the lower part functions being corresponding to the big cover in the former patent, an inside thread hole  22  with the screw base diameter of 24-25 mm forming on the lower inside wall of said big cover  2 , a sucker  15  being provided at the lower part of pump body  1 , a steel bead  16  located inside the upper part of said sucker  15  being engaged with a valve base to form an one-way valve. 
     The head cap  6  is integrated with the big piston  3  by a single forming, a sealing ring  9  made of elastic materials is provided between said big piston  3  and the inside wall of said pump body  1 , i.e., a circular groove  31  is formed along the circumference of said big piston  3 , allowing said sealing ring  9  to slide up and down freely inside said groove  31  easily, which is provided with an air inlets  32  for connection with the outside on the inner lower wall and the bottom, an one-way valve structure is formed with the function of the sealing ring  9  and the air inlet  32  on said circular groove  31 . 
     Said pump body  1  is sleeved in a shield  14 , the big piston  3  of said head cap  6  is located inside the shield cam ring  141 , which sets the upper limit of said big piston  3 , part of said shield  14  corresponding to said pump body  1  and said head cap  6  are engaged flexibly to facilitate air inlet. Said shield  14  is further enclosed by a transparent enclosure  23 . 
     A circular groove  12  with a U-shaped section is formed on the lower part of said pump body  1 , said piston rod  5  is provided with a shoulder  53  in the middle and is sleeved in a spring  13 , which is supported between said circular groove  12  and said shoulder  53 . 
     The lower through hole of said piston rod  5  is connected with the small piston base  18 , which is sleeved by the small piston  4  at the middle slidingly, said small piston  4  adopts double-valve structure, the lower end of the big valve inside it is engaged with the circular groove  181  on said small piston base  18 , to facilitate engagement, said circular groove  181  is provided with a tapered surface on the flange. A shallow groove  182  is formed on the surface of said small piston base  18  to connect the liquid cavity  19  below with the air-liquid mixing cavity  52  above. 
     An one-way valve is provided between said air-liquid mixing cavity  52  of said piston rod  5  and the air cavity  11  of said pump body, moreover, the main body of the one-way valve adopts valve leaves  8  in the sleeve shape made of elastic materials like silica gel, said valve leaves  8  are provided with staged surfaces for installation on said piston rod  5 , besides, the upper parts of said valve leaves  8  become a sealing valve with ascending diameter and a tapered cavity, said through holes  51  are (one or multiple) provided on the piston rod on the side of the sealing surface of the valve, if multiple, the through holes  51  are distributed evenly along the circumference to connect the air-liquid mixing cavity  52  of said piston rod and the air cavity  11 . In this way, the sealing surface on the upper end of valve leaves  8  is in tight engagement with the through holes  51  on said piston rod to form the one-way valve structure. 
     The air hole  21  is provided on the big cover  2  for connection with the outside through the one-way valve  10  inside the big cover  2 , said one-way valve  10  adopts elastic valve and the air hole  21  in tight engagement. 
     To provide interval between the shield  14  and the big cover  2  to facilitate the air hole  21  to allow air in, a shallow groove  22  is provided along the circumference of said big cover  2 , said air hole  21  is provided in said shallow groove  22 . 
     The forming screen  7  is limited in the middle to upper part of the piston rod  5 , please see the Chinese invention patent under patent No. CN 200720113219.8 for details. 
     The head cap  6  is around the piston rod  5  with its lower end telescopically inserted in the pump body  1 , and then the big cover  2  is connected with the bottle jack thread of the case of the atomizer to form the container with the foam pump. 
     The working principles and operation procedure are as follows. 
     When the head cap  6  is pushed, it drives the piston rod  5  to move downwards, the sealing ring  9  on the side of said big piston  3  slides upwards under the friction of the pump body  1 , which separates the air cavity  11  inside said pump body  1  from the outside in the sealed state, in the meanwhile, under the driving force of the piston rod  5 , the compression air cavity  11  of the big piston  3  indirectly connected with the piston rod  5  is provided with increased air pressure, then the air inside it enters the air-liquid mixing cavity  52  in the piston rod after passing the through holes  51  on the piston rod  5  and pushing the valve leaves  8  open, which drives the mixture of air and liquid to form in the foaming screen  7  and the head cap  6  and then sprayed out from the foaming hole of nozzle of the head cap  6 ; the piston rod  5  keeps driving the small piston  4  downwards by overcoming the elastic force of the spring  13 , due to the resistance between the small piston  4  and the inner wall of the sucker  15 , the small piston  4  adopts lagging movement at the beginning and slides relative to the small piston base  18 , it is impossible to realize sealing contact between the lower end of the small piston  4  and the circular groove on the small piston base  18 , besides, the small piston  4  moves downwards, which increases the pressure inside the liquid cavity  19  in the pump body  1 , the steel bead  16  seals the sucker  15 , which prevents the liquid below from entering, however, the liquid in the liquid cavity  19  enters the air-liquid mixing cavity  52  in the piston rod  5  after passing the shallow groove  181  on the surface of the small piston base  18  as driven by the airflow and be mixed with the air from the air cavity  11  into the mixture of air and liquid, which is prepared for the next circle. 
     When the head cap  6  is released, the piston rod  5  moves upwards under the effect of the spring  13 , which drives the piston rod  5  to move upwards, due to the resistance between the small piston  4  and the inner wall of the sucker  15 , the small piston  4  adopts lagging movement at the beginning and slides relative to the small piston base  18 , a second sealing contact between the lower part of the small piston  4  and the circular groove on the small piston base  18  is realized, besides, the small piston  4  moves upwards, which increases the volume of and decreases the pressure inside the liquid cavity  19  in the pump body  1 , it is impossible for the steel bead  16  to seal the sucker  15 , in the meanwhile, the air from the outside applies pressure on the atomizer through the air inlet hole  21  on the big cover  2  to make the liquid below enter the liquid cavity  19  while the liquid in the liquid cavity  19  cannot enter the air-liquid mixing cavity  52  in the piston rod  5  through the shallow groove  181  on the surface of the small piston base  18 , as driven by the piston rod  5 , the big piston  3  also moves upwards, and due to the lagging movement of the sealing ring  9 , it slides downwards, which allows the air form outside to compensate the air in the air cavity  11  after passing the interval between the sealing ring  9  and the groove  31  and the air inlet  32  to make preparation for the next cycle; the spraying is realized by circular motions in order.