Patent Publication Number: US-11389814-B1

Title: All plastic hand pump with a piston having an integrated check valve

Description:
CROSS-REFERENCES TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 63/175,651, filed Apr. 16, 2021 and entitled “All Plastic Mist Sprayer,” which is incorporated here by this reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to hand operated liquid dispensing pumps used in the personal care industry and, in particular, to hand pumps comprised of all plastic components. 
     Background Art 
     Hand operated dispensing pumps are well-known in the personal care industry for dispensing liquids, including liquids in the form of mists, sprays, foams and creams. The majority of pumps for dispensing liquids presently available are made from plastic but include at least a metal compression spring to return the pump actuator to its starting position after being depressed. Typically, hand operated dispensing pumps are preinstalled on a fluid filled container prior to sale and are disposed of along with the container when the contents of the container are depleted. The pumps are not typically intended to be reused. Although pumps using metal return springs operate effectively, and are of relatively low cost to make, they have certain drawbacks. In particular, the steel compression springs typically used in such pumps make the pumps difficult to recycle and may cause rust contamination of the product to be dispensed. 
     Plastic parts are recycled by grinding or shredding the parts. The shredded material may then be reused, typically by melting the material and mixing it with new plastic. To be suitable for grinding or shredding, used plastic must be free of any metal parts. A hand pump using a metal return spring, or any metal components, must be disassembled to remove the metal components prior to recycling the plastic materials which compose the bulk of the pump. The need to disassemble a used hand pump to remove the metal components prior to recycling increases costs and has the effect of decreasing the desirability of used hand pumps as a source of recycled plastic. Thus, there is a need in the art for hand pumps capable of dispensing liquids made of all plastic components. Such pumps would require no disassembly prior to being ground or shredded for use as recycled plastic. 
     SUMMARY OF THE INVENTION 
     The present invention meets a long-felt need in the art by providing a new hand pump design for dispensing liquids where the pump is fabricated entirely from plastic materials. The all plastic hand pump of the present invention, lacking any metal parts, is easy to recycle and also eliminates potential contamination of the product to be dispensed due to rusting of the steel compression springs typically found in prior art hand pumps. 
     The major components of the hand pump of the present invention comprise an actuator, a pump housing configured with a ball style lower check valve, a closure, a piston configured with an integral upper check valve and, a plastic return spring. In use, the hand pump will be mounted on a container containing a liquid to be dispensed and a dip tube will attach to a bottom of the pump housing and into the fluid to be dispensed. 
     The piston of the hand pump is a single injection molded component having a lower portion and an upper portion. The lower portion is configured as a thin wall, hollow, truncated cone which is connected to the upper portion which is configured as a thin wall, hollow cylinder. Suspended within the hollow cylinder of the upper portion is a hollow, inverted cone. The suspended inverted cone functions as the upper check valve. 
     The actuator of the hand pump includes a nozzle, wherein the actuator has a center tube having upper and lower ends. The upper end of the center tube is in fluid communication with the nozzle and the lower end of the center tube is in fluid communication with the upper portion of the piston. The exterior of the lower end of the center tube slides within the interior of the upper portion of the piston and the interior of the lower end of the center tube slides over the inverted cone suspended within the upper portion of the piston. This configuration allows air or fluid to pass between an interior cylindrical wall of the center tube and an upper circumference of the inverted cone, when the pump housing is pressurized on a downstroke of the actuator and consequently the piston which is connected thereto. 
     The piston reciprocates within a bore of the pump housing, which is configured with a ball style check valve at its lower end. The pump housing is connected to the collar, which includes threads for attachment to a container of fluid to be dispensed. Disposed between the collar and actuator and about the piston is the plastic return spring. 
     The hand pump of the present invention operates as follows. Assuming the pump is dry or unprimed, in a first step, a user presses downwardly on the actuator. Downwards motion of actuator simultaneously compresses the plastic return spring and causes the piston to move downwardly, as well. As the piston moves downwardly, pressure increases inside the pump housing which causes the lower check valve to close and the upper check valve to open forcing air to exit thru the orifice. 
     The upper check valve comprises the inverted cone suspended within the upper portion of the piston. The wall of the inverted cone is flexible and consequently, as a downstroke of the actuator pressurizes the housing, any air or fluid within the housing passes by the interface between the upper circumference of the inverted cone and the interior wall of the center tube of the actuator and subsequently through the center tube and out the nozzle. On a first actuation of a dry pump, air passes the upper check valve. On subsequent actions, fluid passes through the upper check valve. 
     In a second step, the actuator is released. When the actuator is released, the plastic return spring drives the actuator and the piston connected thereto upwardly. As the piston moves upwardly, the upper check valve is sealed causing vacuum inside the housing, which in turn causes the lower check valve to open and the liquid to be dispensed is then drawn up from the container into the pump housing via the dip tube which is attached to the bottom of the pump housing and which extends into the volume of liquid held within the container. 
     In the third step, the actuator is pressed downwardly a second time. As the actuator is pressed downwardly, the plastic spring is compressed and the piston connected to the actuator moves downwardly as well. Downwards movement of the piston causes pressurization of the pump housing. Pressurization causes the bottom check valve to close and the upper check valve to open. The liquid in the housing, previously draw up from the container in step  2 , is forced through the upper check valve and exits the pump through an orifice of the nozzle. After the hand pump is initially primed in step one, each subsequent down stroke and up stroke cycle of the actuator will cause liquid in the housing to be dispensed from the nozzle and fresh liquid to be drawn from the container into the housing. 
     The above and other advantages of the all plastic hand pump of the present invention will be described in more detail below. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an exemplary perspective view of the hand pump of the present invention. 
         FIG. 2A  is a cross-sectional view of the hand pump of the present invention with the actuator in the raised or at rest position. 
         FIG. 2B  is a cross-sectional view of the hand pump of  FIG. 2A , showing the actuator in depressed position. 
         FIG. 3A  is cross-sectional view of the piston of the hand pump of  FIG. 2A . 
         FIG. 3B  is a top view of the piston shown in  FIG. 3A . 
         FIG. 4A  is cross-sectional view of the actuator of the hand pump of  FIG. 2A . 
         FIG. 4B  is a top view of the actuator of shown in  FIG. 4A . 
         FIG. 5A  is cross-sectional view of the pump housing of the hand pump of  FIG. 2A . 
         FIG. 5B  is a top view of the pump housing shown in  FIG. 5A . 
         FIG. 6A  is cross-sectional view of the closure of the hand pump of  FIG. 2A . 
         FIG. 6B  is a top view of the closure shown in  FIG. 6A . 
         FIG. 7A  is cross-sectional view of the plastic return spring of the hand pump of  FIG. 2A . 
         FIG. 7B  is a top view of plastic return spring shown in  FIG. 7A . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. The invention however, may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. 
     Description of the Component Parts 
     With reference to  FIGS. 1-7B , the hand pump  10  of the present invention comprises an actuator  12 , a pump housing  14  configured with a ball style lower check valve  16 , a closure  18 , a piston  20  configured with an integral upper check valve  22  and, a plastic return spring  24 . Typically, the hand pump  10  will be mounted on a dispenser container  26 , containing a liquid  28 . The hand pump  10  draws the liquid  28  from the dispenser container  26  via a dip tube  30 . 
     With reference to  FIGS. 2A-2B and 3A-3B , the piston  20  of the hand pump  10  is an injection molded component having a lower portion  34  and an upper portion  32 . The lower portion  34  is configured as a thin wall, hollow, truncated cone having a lower circumference  36 . The upper portion  32  is configured as a thin wall, hollow cylinder having an upper lip  38 . Suspended within the upper portion is the check valve  22 . The upper check valve  22  is configured as a hollow inverted cone having a flexible wall  42  and an upper circumference  40 . The hollow inverted cone which forms the upper check valve  22  has a truncated end  114  with a cylindrical cavity  116  extending downwardly therefrom. The central cavity  116  allows for pre-compression of the fluid to be dispensed. The piston  20  also includes a central post  118  and fins  120  to direct the flow of fluid to be dispensed and reduce turbulence. The fins  120  suspend the upper check valve  22  within the upper portion  32  of the piston  20  and suspend the central post  118  within the lower portion  34  of the piston  20 . The piston  20  further includes annular steps  122  which assist in controlling the shape of the piston during molding of the part. 
     With reference to  FIGS. 2A-2B and 4A-4B , the actuator  12  of the hand pump  10  includes a nozzle  45  having a flow passage  44  which is in fluid communication with a center tube  46 . The flow passage  44  has a first end  54  and a second end  56 . The first end  54  includes an exit orifice  50 . The exit orifice  50  may be configured to dispense pressurized liquid  28  from the hand pump  10  in a variety of forms such as a fan spray, jet spray or in the form of an atomized mist, or the like. 
     The actuator  12  also includes a ring element  104  which features at least one air vent  110  formed in the ring element  104 . In the exemplary embodiment, a plurality of the at least one air vents  110  is disposed radially about the perimeter of the ring element  104 . The at least one air vent  110  vents the volume of the pump body  14  above the level of the piston  20  to atmosphere. 
     The center tube  46  of the actuator  12  has an upper end  52  and a lower end  48 . The upper end  52  is has a cylindrical interior surface  58  and the lower end  48  has a conical interior surface  60  and cylindrical exterior surface  62 . The upper end  52  of the center tube  46  is in fluid communication with the flow passage  44  of the nozzle  45  at its second end  56  and the lower end  48  of the center tube is in fluid communication with the upper portion  32  of the piston  20 . 
     With reference to  FIGS. 2A-2B, 3A-3B and 4A-4B , the actuator  12  interfaces with the piston  20  as follows. The cylindrical exterior surface  62  of the lower end  48  of the center tube  46  slides within a cylindrical interior surface  64  of the upper portion  32  of the piston  20  and the conical interior surface  60  of the lower end  48  of the center tube  46  slides over the upper circumference  40  of the upper check valve  22 , where the upper check valve  22  is configured as an inverted cone suspended within the upper portion  32  of the piston  20 . The conical interior surface  60  of the lower end of the center tube  46  at least partially overlaps the inverted cone of the upper check valve  22 . This configuration allows air or the liquid  28  to pass between the conical interior surface  60  of the center tube  46  and the upper circumference  40  of the upper check valve  22 , when pump housing  14  is pressurized on a downstroke of the actuator  12 . 
     With reference to  FIGS. 2A-2B and 5A-5B , the pump housing  14  is a generally hollow, cylindrical housing having an upper body  70  and a lower body  72 . The upper body  70  is configured as a cylindrical bore having an internal volume  68  and the lower body  72  is configured as a tube. The upper body  70  is open at an upper end  92  and transitions to the lower body  72  at a lower end. The upper end  92  of the upper body  70  is configured to engage with the pump housing  14  via a snap fit. The lower body  72  includes the lower check valve  16  which incorporates a plastic ball  74  to open and close an orifice  106  formed within the lower body  72 , in response to pressure changes in the upper body  70 . The lower body  72  is open at a lower end and is configured to accept the dip tube  30 . The upper body  70  includes at least one vent hole  108 , which vents the interior volume  68  to atmosphere on a downstroke of the actuator  12 . 
     With reference to  FIGS. 2A-2B and 6A-6B , the closure  18  of the present invention hand pump  10  comprises a generally circular lower portion  76  and a generally circular upper portion  78 . The generally circular lower portion  76  includes screw threads  80  which interface the hand pump  10  with the dispenser container  26  containing the liquid  28  to be dispensed. The generally circular upper portion  78  includes a circular retaining channel  82  which retains a lower edge  84  of the plastic return spring  24 . The closure  18  also includes an upper shelf portion  88  which includes a circular opening  86 . When assembled the piston  20  is disposed through the circular opening  86  and into the upper body  70  of the pump housing  14 . The closure also includes a lower ring-wall  90  which is configured to attach to the upper body  70  of the pump housing  14  via a snap fit. 
     With reference to  FIGS. 2A-2B and 7A-7B , the plastic return spring  24  of the present invention hand pump  10  comprises a generally dome-shaped body portion  94  with a neck portion  96 . The plastic return spring  24  includes an upper opening  98  formed in the neck portion  96  and a lower circumference  100 . The upper opening  98  of the neck portion  96  is configured to be in a slip fit relationship with the cylindrical exterior surface  62  of the center tube  46  of the actuator  12  (see  FIG. 4A ). The neck portion  96  includes a ring-shaped surface  102  which abuts a ring-shaped face  105  of the actuator  12 . The lower edge  84  of the plastic return spring  24  is retained within the circular retaining channel  82  (see  FIG. 6A ) of the closure  18 . As shown in  FIGS. 2A  and particularly  2 B, the plastic return spring  24  functions as a compression spring. In the exemplary embodiment, the plastic return spring  24  is made from elastic materials such elastomers and plastomers. Other elastic materials are also suitable. 
     Assembly of the Hand Pump 
     With reference to  FIGS. 2A and 2B and 3A to 7B , in a first step, the plastic ball  74  is placed in the lower check valve  16  formed in the lower body  72  of the pump housing  14 . In a second step, the piston  20  is placed in the cylindrical bore of the upper body  70  of the pump housing  14 . 
     In a third step, the pump housing  14  is snapped into the closure  18 , i.e. the upper end  92  of the upper body  70  of the pump housing  14  is engaged with the lower ring-wall  90  of the closure  18  via a snap fit. 
     In a fourth step, the plastic return spring  24  is added to the closure  18 , i.e. the lower circumference  100  of the plastic return spring  24  is seated within the circular retaining channel  82  of the closure  18 . 
     In a fifth step, the actuator  12  is connected to the piston  20 . In particular, the lower end  48  of the center tube  46  is configured to slide within the upper portion  32  of the piston  20  and engage via a snap fit with the upper lip  38  of the upper portion  32  of the piston  20 . When assembled, the ring-shaped face  105  of the ring element  104  of the actuator  12  abuts the ring-shaped surface  102  of the plastic spring  24 . 
     Operation of the Hand Pump 
     The hand pump  10  of the present invention has two strokes, i.e. a downstroke and an upstroke, which cause the piston  20  to reciprocate within the upper body  70  of the pump housing  14 . A downstroke of the actuator  12  and the piston  20  connected thereto, opens the upper valve  22  and closes the lower valve  16  and thereby pressurizes the internal volume  68  of the pump housing  14 . The pressurized contents of the internal volume  68  of the pump housing  14  are consequently forced through the upper check valve  22  and out of the nozzle  45  of the actuator  12 . On an upstroke, the upper check valve  22  closes and the lower check valve  16  opens, which causes the liquid  28  in the dispenser container  26  to be drawn into the upper body  70  of the pump housing  14  via the dip tube  30  which is in fluid communication with the dispenser container  26  and the upper body  70 . 
     With reference to  FIGS. 2A and 2B , and assuming the pump has not previously been used, i.e. is dry or unprimed, the hand pump  10  of the present invention operates as follows. In a first step, a user presses downwardly on the actuator  12 . Downwards movement of actuator  12  simultaneously compresses the plastic return spring  24  and causes the piston  20  to move downwardly, as well. As the piston  20  moves downwardly, pressure increases inside the upper body  70  of the pump housing  14  which causes the lower check valve  16  to close and the upper check valve  22  to open forcing air in the upper body  70  to exit thru the nozzle  45 . 
     The upper check valve  22  comprising an inverted cone suspended within the upper portion  32  of the piston  20  is flexible and consequently, as a downstroke of the actuator pressurizes the pump housing  14 , any air or fluid within the pump housing  14  passes by the interface between the upper circumference  40  of upper check valve  22 , i.e. of the inverted cone, and the interior wall  60  of the center tube  46  of the actuator  12  and subsequently through the center tube  46  and out the nozzle  45 . On a first actuation of a dry pump, air passes the upper check valve  22 . On subsequent downstrokes, fluid passes through the upper check valve  22 . 
     In a second step, the actuator  12  is released. When the actuator  12  is released, the plastic return spring  24  drives the actuator  12  and the piston  20  connected thereto upwardly. As the piston  20  moves upwardly, the upper check valve  22  is sealed causing vacuum to be generated inside the pump housing  14 , which in turn causes the lower check valve  16  to open and the liquid  28  to be dispensed is then drawn up from the dispenser container  26  into the pump housing  14  via the dip tube  30  which is attached to the lower body  72  of the pump housing  14  and which extends into the volume of liquid  28  held within the dispenser container  26 . 
     In a third step, the actuator  12  is pressed downwardly a second time. As the actuator  12  is pressed downwardly, the plastic return spring  24  is compressed and the piston  20  connected to the actuator  12  moves downwardly as well. Downwards movement of the piston  20  causes pressurization of the pump housing  14 . Pressurization causes the lower check valve  16  to close and the upper check valve  22  to open. The liquid  28  in the pump housing  14 , previously drawn up from the container in step  2 , is forced through the upper check valve  22  and exits the hand pump  10  through the exit orifice  50  of the nozzle  45 . After the hand pump  10  is initially primed in step one, each subsequent downstroke and upstroke cycle of the actuator  12  will cause liquid  28  in the upper body  70  of pump housing  14  to be dispensed from the nozzle  45  and fresh liquid  28  to be drawn from the dispenser container  26  into the pump housing  14 . 
     Venting of the Hand Pump 
     With reference to  FIGS. 2A, 2B, 4A and 5A , the hand pump  10  of the present invention is equipped with the at least one air vent  110  formed in the ring element  104  of the actuator  12  which allows air communication between the atmosphere and the interior volume  68  of the pump housing  14  and the interior volume of the dispenser container  26 , via the at least one air vent hole  108  of the pump housing  14 . It is necessary to equalize the pressure of the interior of the pump body and the interior of the container to allow the hand pump  10  to properly operate. 
     The vent system of the all plastic hand pump  10  operates as follows: In the at rest position (see  FIG. 2A ), the piston  20  blocks the at last one air vent hole  108  of the pump housing  14 . When the actuator  12  is pushed downwardly, the piston  20  moves downwardly, uncovering or opening the at least one air vent hole  108  in the pump housing  14 . Due to a pressure differential between the atmosphere and the interior of the dispenser container  26  on a downstroke of the actuator, air will flow from the atmosphere via the at least one air vent  110  and the at least one air vent hole  108  to the inside of the dispenser container  26 . 
     While the present invention has been described with regards to particular embodiments, it is recognized that additional variations of the present invention may be devised without departing from the inventive concept.