Abstract:
Apparatuses and techniques are provided for dispensing fluid from a dispenser that includes a flexible membrane having different levels of pliability according to a voltage applied to the flexible membrane. According to some embodiments, a biasing device, such as a spring, is disposed on a first side of the flexible membrane and is configured to apply pressure to the flexible membrane. When a first voltage is applied to the flexible membrane, the flexible membrane becomes sufficiently pliable to enable the spring to flex the flexible membrane, pushing the flexible membrane into a pumping chamber disposed on the opposite side of the flexible membrane relative to the spring. The fluid is stored in the pumping chamber and the flexing of the flexible membrane causes the pumping chamber to compress. Such compression of the pumping chamber forces the pumping chamber to dispense the fluid through a pump outlet.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a non-provisional filing of and claims priority to U.S. Provisional Application 61/880,270, titled “DISPENSER PUMP USING ELECTRICALLY ACTIVATED MATERIAL” and filed on Sep. 20, 2013, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The current invention pertains to pumping mechanisms used in fluid product dispensers, and more specifically to pumping mechanisms that use electrically activating polymers to pressurize a fluid chamber for dispensing fluid product through a nozzle. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is known in the art to dispense hand care products from a dispenser mounted to a wall or stand. Such dispensers typically have a replaceable reservoir containing hand soap, lotion or sanitizer. Some models dispense product automatically by sensing when a person&#39;s hand has been placed under the dispenser. The sensor sends signals to a controller, which in turn operates a pump that forces fluid through a nozzle and onto the person&#39;s hand. 
         [0004]    Dispensers may be conveniently located in building entrances, bathrooms, or lunchrooms providing convenient accessibility to passersby. However, not all areas are appropriately suited for supplying power to dispensers. As such, dispensers are typically equipped with an onboard power source, typically batteries. 
         [0005]    However, drain on the batteries can be significant. Pumps are actuated by motors, which include gears or other forms of transmission inherently possessing significant power losses. Sensors and control circuitry add additional drain to the onboard power source. Thus, frequent maintenance of the automatic dispensers is needed and cost is incurred with the regular replacement of batteries. 
         [0006]    Moreover, traditional pump actuators are relatively large, precluding the use of automatic dispensers in areas where limited space is available. 
         [0007]    It would therefore be advantageous to provide an automatic dispenser having a low power consumption profile and a small foot print, while maintaining the functional benefits of a touch-less dispenser. The present invention obviates the aforementioned problems. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a fluid product dispenser according to the embodiments of the present invention. 
           [0009]      FIG. 2  is a cross-sectional view of the fluid product dispenser showing the internal components of the dispenser. 
           [0010]      FIG. 3  is a cross-sectional view showing a schematic representation of a fluid product pump in the electrically de-energized state according to the embodiments of the present invention. 
           [0011]      FIG. 4  is a cross-sectional view showing a schematic representation of a fluid product pump in the electrically energized state according to the embodiments of the present invention. 
           [0012]      FIG. 5  is a cross-sectional view showing a schematic representation of another embodiment of the fluid product pump according to the embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    With reference to  FIG. 1 , a product dispenser according to the embodiments of the present invention is shown and indicated generally at  10 . Dispenser  10  meters out product, which may include hand care products like soap, lotions or sanitizers, although other types of fluid products may be dispensed from the product dispenser. 
         [0014]    Referencing  FIGS. 1 and 2 , dispenser  10  includes a base  14  and a cover  18  which when closed define an internal area that holds the components of the dispenser  10 . The base  14  may be generally rigid having a structural configuration suitable for supporting a pump and a fluid reservoir  30 , as well as other components to be discussed later. The dispenser  10  can be mounted to a wall, stand or other structure, not shown in the figures, and so the base  14  includes mounting holes or brackets capable of receiving one or more fasteners. The base  14  may further include a hinge  22  onto which the cover  18  is pivotally attached. A latch  26  secures the  18  cover in place and manually releases to allow access to the interior region of the dispenser  10 . In one exemplary manner, the cover  18  may be generally concave and may include a window  11  positioned to allow service personnel visual access to the fluid reservoir  30 . 
         [0015]    Still referencing  FIG. 2 , fluid reservoir  30  is constructed to contain hand care products. The reservoir  30  may be a reusable container and refilled with product as needed. Alternatively, the reservoir  30  may be disposable and replaced when empty. Access to the reservoir  30  is gained by unlatching and pivoting the cover  18  away from the base  14  thereby exposing the interior of the dispenser  10 . In one embodiment, the reservoir  30  may held in place by a ledge and/or wall extended from the base  14 . Generally, the reservoir  30  is removed and replaced with another reservoir  30  for sanitary reasons. Such replaceable reservoirs are referred to hereafter as refill units  34 . 
         [0016]    The refill unit  34  may be constructed from pliable sheet-like material, referred to as a bag, and may include an outlet attached to a side or an end of the bag. Still other refill units  34  may be constructed from generally rigid or semi-rigid plastic for use in an upright or an inverted mounting configuration. In  FIG. 2 , the refill unit  34  is stored completely within the dispenser housing. However, other structural and mounting configurations for the refill unit  34  may be selected without departing from the intended scope of coverage of the embodiments of the present invention. 
         [0017]    Referring now to  FIGS. 2 and 3 , an exemplary embodiment of a dispenser pump  40  is shown having a pump inlet  42  and a pump outlet  46 . The pump outlet  46  is connected to a nozzle  47  for dispensing fluid product from the dispenser  10 . The pump inlet  42  is fluidly connected to the refill unit  34 . More specifically, the pump inlet  42  is connected to an end of the refill unit  34  to minimize waste. In one embodiment, the pump  40  is disposable and is provided attached to the refill unit  34  as an assembly. In this manner, every wetted component of the dispenser  10  is disposed of when the refill unit  34  is replaced. 
         [0018]    Still referencing  FIG. 3 , pump  40  includes a pumping chamber shown generally at  50 . In the embodiment currently described, pumping chamber  50  has a generally concave region  52 . Inlet  42  extends from a top side of the concave region  52  and outlet  46  extends from the distal bottom end of the concave region  52 , although other positions of the inlet and outlet relative to the pumping chamber  50  may be chosen with sound judgment. In this way, gravity assists in drawing product from the refill unit  34  into the concave region  52 . An actuator, discussed in detail below, pressurizes chamber  50  thereby expelling product through the outlet  46  and the nozzle  47 . It will be appreciated that other configurations of pumping chambers  50  may be used without departing from the intended scope of coverage of the embodiments of the present invention. 
         [0019]    Fluid in the pumping chamber  50  may be pressurized by displacing one or more walls that make up the pumping chamber  50 . In the preferred embodiment, chamber  50  may be constructed from one or more rigid wall sections  53  and by a flexible membrane  70 . Pressure is generated in the concave region  52  from a biasing device  54  located adjacent the flexible membrane  70 . In one embodiment, biasing device  54  comprises a leaf spring, or a coil spring  55 . However, other types of springs or biasing devices may be used. Force from the biasing device  54  pushes against the membrane  70  constricting the volume of fluid in the chamber  50  thereby pressurizing the product inside. 
         [0020]    With continued reference to  FIG. 3 , membrane  70  is constructed from flexible polymeric material. The flexible material possesses memory and has a predetermined stiffness, i.e. resistance to bending. In one embodiment, membrane  70  is made from Silicone, or alternatively from Polyurethane. However, it should be construed that other types of material that have the requisite characteristics of stiffness and memory may be used as needed for operation of the pump  40 . Accordingly, after membrane  70  is displaced, i.e. biased by device  54 , it will tend to retain its original shape and return to its unbiased configuration when the force is removed. It will be appreciated that the spring constants of the biasing device  54  may be matched to the stiffness of the membrane  70  in a manner suitable for operation of the dispenser  10  as described herein. 
         [0021]    The membrane  70  further includes electrically conductive material applied to each of its opposing faces  70 ′,  70 ″. In one embodiment, the electrically conductive material comprises carbon particles adhered to the surface of the membrane in a relatively thin layer. Each face  70 ′,  70 ″ of the membrane, and more specifically each of the electrically conductive layers  72 , is respectively connected to opposite polarity terminals of a DC voltage power source. When a threshold magnitude of voltage is applied to the membrane  70 , its stiffness is altered by the attraction of the conductive layers  72  pressing together. As such, the membrane  70 , in effect, temporarily loses some of its stiffness becoming more pliable and therefore subject to displacement from the force of the biasing device  54  (reference  FIG. 4 ). Consequently, when the voltage potential is removed the memory of the base material returns the membrane  70  to its original shape thus overcoming the bias force (reference  FIG. 3 ). It can be readily seen then that energizing and de-energizing the voltage source results in the compression and de-compression of the pumping chamber  50  thereby facilitating pumping of product from the dispenser  10 . 
         [0022]    It will be understood by persons of skill in the art that the polymeric material of the membrane  70  functions as a dielectric between the electrically conductive layers  72 . The polarizing effect of the applied voltage alters the characteristics of membrane  70  as described above. Voltages applied to the membrane  70  may be in the range of 2 kV to 4 kV. However, any range of voltage potential may be applied as is appropriate for use in actuating the pump  40 . In that the phenomenon of altering the stiffness of a dielectric polymer by the application of voltage is known in the art, no further explanation will be offered here. 
         [0023]    To ensure that product flows properly through the nozzle  47 , one or more valves are incorporated into pump  40 . In one embodiment, a first valve, shown generally at  80 , is fluidly communicated with inlet  42 . Additionally, a second valve, shown generally at  81 , is fluidly connected to outlet  46 . When activated in proper succession, the valves  80 ,  81  prevent the back flow of product into refill unit  34  and prevent product from leaking through the nozzle before the dispenser is activated. 
         [0024]    With reference again to  FIGS. 3 and 4 , membrane  70  may be used as valves  80 ,  81  to selectively open and close inlet  42  and outlet  46  as mentioned above. In one embodiment of the present invention, an additional biasing device  57  may be positioned adjacent to membrane  70  and in proximity to inlet  42 . When voltage is applied to the conductive layers  72  in a manner previously described, membrane  70  loses stiffness over the entire area covered by the conductive layers  72 . Accordingly, membrane  70  becomes more pliable allowing biasing device  57  to press membrane  70  into sealing contact with the inlet  42  thereby preventing fluid flow back into the refill unit  34 . 
         [0025]    It is noted that biasing devices  54  and  57  displace membrane  70  at the same time. Accordingly, it is contemplated in an alternate embodiment that one single biasing device, not shown in the figures, may be used to both displace fluid from the pumping chamber  50  and seal the inlet  42 . Thus the biasing device may be specifically configured and the inlet  42  may be positioned proximal to the pumping chamber to facilitate both actions with a single biasing element. 
         [0026]    Referring still to  FIGS. 3 and 4 , another separate biasing device  59  may be included and positioned to engage membrane  70  at the location of the outlet  46 . It is noted that the inlet  42  and outlet  46  must be fluidly sealed at opposite times during operation of the pump  40 . Hence, biasing device  59  is positioned to move membrane  70  away from the outlet  46  when fluid in the pumping chamber  50  is pressurized. It follows that, in the de-energized state, membrane  70  is configured to cover the outlet  46  thereby preventing fluid flow therethrough. 
         [0027]    With reference now to  FIGS. 3 and 5 , to ensure against leaks through outlet  46  in the de-energized state, a raised rim  49  may be positioned around the opening of the outlet  46 . Additionally, protrusions, referred to herein as ribs  51 , may be fashioned to extend from the one or more rigid wall sections  53  opposite that of the raised rim  49 . In this way, the stiffness and memory of the membrane  70  force it into contact with the outlet  46  in a crimping action (reference  FIG. 5 ). 
         [0028]    It will be appreciated that pressurized fluid will act on the membrane  70  to move it out of engagement with the outlet  46 . As such,  FIG. 5  depicts an embodiment of the present invention that does not include a dedicated biasing device to force the membrane  70  out of engagement with the outlet  46 . Accordingly, the stiffness and/or thickness of the membrane  70  may be selected so that as pressure in the pumping chamber  50  increases, a threshold is reached that overcomes the rigidity of the membrane  70  thus allowing fluid to flow through the nozzle  47 . While the current embodiment depicts both rim  49  and ribs  51 , variations are contemplated excluding one or the other of these components. 
         [0029]    Having illustrated and described the principles of this invention in one or more embodiments thereof, it should be readily apparent to those skilled in the art that the invention can be modified in arrangement and detail without departing from such principles.