Patent Publication Number: US-8113389-B2

Title: Anti drip fluid dispenser

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to a fluid dispenser having an anti-drip feature. 
     BACKGROUND OF THE INVENTION 
     Fluid dispensers are known in the art for dispensing various viscous liquid and foam compositions. The viscous liquid and foam compositions are typically soaps, shampoos, creams, or lotions and are often found in public restrooms, restrooms in office buildings, and the like. One problem facing these fluid dispensers is at the end of a dispensing cycle a small portion of the fluid being dispense from the dispenser may remain at the exit port of the dispensing nozzle. This small portion of the fluid being dispensed can result in a condition called “stringing”, in which the small portion of the fluid remains attached to the fluid dispensed to the user. For example, when the fluid is dispensed into the user&#39;s hand, the small portion of fluid remains attached to both the fluid dispensed in the user&#39;s hand and the exit port of the nozzle. As the user withdraws their hand away from the exit port, the small portion of the fluid remains attached to both the user&#39;s hand and the exit port of the nozzle, creating an elongated string-like formation of the fluid. Stringing is especially a problem with foam compositions. Stringing can confuse a user, causing the user to focus on terminating the string, rather than the job at hand, for example, washing one&#39;s hands. 
     Alternatively, the small portion of the fluid may remain solely at the exit port of the nozzle. As gravity or other forces act on this small portion of the fluid, the small portion of the fluid may drip from the exit port of the nozzle onto a structure located beneath the exit port, such as a floor, a countertop, or sink. Alternatively, the small portion of the fluid may from a “string” of the fluid form the exit port to the structure beneath the exit port of the nozzle. In each of these situations, the viscous liquid dispenser gives the appearance of wasting the fluid and/or being of poor quality. In addition, having the fluid on surface beneath the nozzle of the dispenser and/or hanging from the exit port of the dispenser is often unsightly, creating a perception of an unclean restroom, and/or presenting a slip hazard to users of the restroom, when the fluid falls to the floor of the restroom. 
     In response to the dripping and stringing problems, pumps have been developed that have a suck back mechanism. This suck back mechanism creates a suction which draws the small portion of undispensed fluid away from the exit port. The prior art suck back mechanisms where built directly into the pump which draws the fluid from a reservoir. These mechanisms used the recovery/recharging cycle of the pump to draw the small portion of the undispensed fluid back towards the pump. One problem with this configuration is that the opposite forces are being applied to the pump at the same time, which may result in the pump with the suck back mechanism built into the pump operating in a manner which is undesirable. That is, the pump is caused to draw fluid from the reservoir at the same time the pump is drawing the portion of the undispensed fluid from the exit port of the dispensing nozzle. These opposite forces may make the pump susceptible to sticking or ineffectively drawing the fluid from the reservoir. As a result, to ensure proper operation of the pump, the prior suck back mechanisms have a complex structure. 
     There is a need in the art for a fluid dispenser with a suck back mechanism which operates independently from the pump mechanism and which has a relatively simple structure. 
     SUMMARY OF THE INVENTION 
     Generally stated, the present invention provides a dispenser for dispensing a fluid. The dispenser has a reservoir, a pump, a suck back mechanism, and a dispensing end. The reservoir is capable of holding a fluid which is to be dispensed from the dispensers. The pump is in communication with the reservoir. The pump has an inlet, an outlet and a recovery means. In addition, the pump has an idle or rest stage, a discharging stage, in which a shot of the fluid is expelled from the pump through the outlet, and a charging stage, in which a shot of the fluid is drawn from the reservoir through the inlet into the pump. The recovery means returns the pump to the idle stage from the discharging stage and through the charging stage. The suck back mechanism is separate from the pump. The suck back mechanism has at least one resilient member capable of storing fluid, a first opening, and a second opening. The first opening of the suck back mechanism is connected to the outlet of the pump and the resilient member is positioned between the first opening and the second opening of the suck back mechanism. The dispensing end of the dispenser has an exit port which allows the fluid to be dispensed from the dispenser and the dispensing end is connected, directly or indirectly, to the second opening of the suck back mechanism. At the end of the discharging stage of the pump, undispensed fluid remains between the dispensing end and the second opening of the suck back mechanism and a portion of the undispensed fluid is drawn into resilient member, independent of the recovery means of the pump. 
     In one embodiment of the present invention, the present invention provides a dispenser where the resilient member is prepared from an elastomeric material. The resilient member is a hollow member having a hollow portion and the hollow portion is capable of storing fluid. The resilient members of the present invention may be shaped to effectively store, intake and release fluids. In one particular embodiment of the present invention, the resilient members may have a corrugated shape or truncated cone shape. 
     In a further embodiment of the present invention, the suck back mechanism may be a single resilient member or a plurality of resilient members. In one particular embodiment, there are two resilient members present in the suck back mechanism. 
     In another embodiment of the present invention, the pump recovery means may be a compressible member. One example of a compressible member that may operate as the pump recovery means is a spring. 
     In another embodiment of the present invention, the suck back mechanism is a body having a first opening, a second opening, and a primary fluid pathway between the first and second opening. This primary pathway connects the first and second openings to one another. Also present is at least one secondary pathway having a first end and a second end, wherein the resilient member is located at the second end of the secondary pathway and the first end of the secondary pathway is located along primary fluid pathway. 
     In an additional embodiment of the present invention, the pump further has a housing having a fluid chamber comprising an interior wall, a piston positioned within the fluid chamber and a piston which is telescopingly movable within the fluid chamber. The piston creates a seal with the interior wall of the fluid chamber. The pump further has an inlet valve located at or near the inlet of the pump, and an outlet valve located at or near the outlet of the pump. In yet a further embodiment of the present invention, the housing further forms a second chamber having an interior wall. The piston is telescopingly movable within the second chamber and creates a seal with the interior wall of the second chamber. This second chamber has a second inlet and a second outlet, wherein the second outlet is located at or near the outlet of the pump and the second inlet is positioned within the pump such that it is on a side of the pump which does not come into contact with the fluid within the reservoir. In one particular embodiment of the present invention, the second inlet is an air inlet, which is adapted to allow atmospheric air to enter the second chamber of the pump, but will not allow atmospheric air in the second chamber to escape through the second inlet. 
     By providing the dispenser of the present invention, drawbacks of the dispensers with suck back mechanisms described above are minimized or eliminated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view a dispenser for dispensing a fluid having a suck back mechanism. 
         FIG. 2  is a cut-away view of a pump and suck back mechanism usable in a dispenser. 
         FIG. 3  shows a perspective view of the top portion of the dispenser with the cover removed. 
         FIG. 4  shows a perspective view of the top portion of the dispenser with the cover and the pump actuator removed. 
         FIGS. 5 and 5A  each show an exploded view of a suck back mechanism usable in the present invention. 
         FIG. 6  shows a perspective view of the top portion of the dispenser with the cover removed and having a single resilient member. 
         FIG. 7  shows a plan view of a corrugated shaped resilient member. 
         FIG. 8  shows a plan view of a truncated cone shape resilient member. 
         FIG. 9  shows a dispenser of the present invention in an in-counter configuration. 
         FIG. 10  shows a dispenser of the present invention with a motor and power supply. 
         FIG. 11A  shows a front view of a motor power transmission system usable in the present invention. 
         FIG. 11B  shows a side view of an actuator drive wheel and an actuator guide member of an embodiment of the present invention. 
         FIG. 11C  shows a back side view of an actuator guide member of an embodiment of the present invention. 
         FIG. 11D  shows a top view of a motor power transmission system embodiment usable in the present invention. 
     
    
    
     DEFINITIONS 
     It should be noted that, when employed in the present disclosure, the terms “comprises”, “comprising” and other derivatives from the root term “comprise” are intended to be open-ended terms that specify the presence of any stated features, elements, integers, steps, or components, and are not intended to preclude the presence or addition of one or more other features, elements, integers, steps, components, or groups thereof. 
     As used herein, the term “fluid” is intended to mean a body of material which is flowable at or about room temperature and pressure. The term is intended to mean gases, liquids and mixtures thereof as well as these materials that contain solids or particles. The term “precursor to the fluid” is intended to mean a material that forms a fluid when expelled from the dispenser. For example, a liquid may be a precursor to a foam dispensed from the dispenser. 
     As used herein, the term “charging stage” is intended to mean a phase of the pump in which fluid is being drawn from the reservoir, and, when the pump is a foaming pump, air being drawn into the air chamber of the pump. 
     As used herein, term “discharging stage” is intended to mean a phase of the pump in which fluid is being expelled from the pump through the outlet of the pump, and, when the pump is a foaming pump, air is being forced from the air chamber of the pump. 
     As used herein, the terms “idle stage” or “rest stage” is intended mean a phase of the pump in which the pump is neither charging or discharging a fluid. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description of the present invention, reference is made to the accompanying drawings which form a part hereof, and which show by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that mechanical, procedural, and other changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled. 
     Referring to  FIGS. 1 ,  2 , and  3 , provided by the present invention is a dispenser  10  for dispensing a fluid. Generally, the dispenser  10  has a reservoir  12 , a pump  14  (shown in  FIG. 2 ), a suck back mechanism  16  and a dispensing end  18 . The reservoir  12  is capable of holding a fluid  22  (shown in  FIG. 2 ) which is to be dispensed from the dispenser  10 . The pump  14  is in communication with the reservoir  12  such that the pump  14  may draw the fluid from the reservoir  12  into the pump, through dip tube  67 . 
     In one embodiment, referring to  FIGS. 1 and 3 , reservoir  12  includes a main container  121  and a top portion  122 .  FIG. 1  shows the top portion  122  on the main container  121  and  FIG. 3  shows the top portion removed from the main container  121 , so that the internal works of the reservoir may be viewed. The main container  121  serves to hold and contain the fluid or the precursor to the fluid that is to be dispensed from the dispenser  10  and will generally have an opening, which is not shown in  FIGS. 1 and 3 . The main container may also have a neck  124  near the opening, wherein the neck  124  of the main container forms the opening in the main container  121 . Generally, the top portion  122  is attachable to the main container  121  at neck  124  of the main container  121 . The top portion  122  may be secured to the main container  121  in a manner such that the top portion  122  is removably secured to the main container  121  or such that the top portion  122  is permanently secured to the main container  122 . For example, the top portion  122  may be sealed to main container  121  using ultrasonic welding, adhesive or other suitable means of effecting a permanent attachment of the top portion  122  to the main container  121 . If it is desirable that the top portion  122  is removable from the main container  121 , the top portion  122  could be mated to the main container  121  using known methods, such as providing threads (not shown) on the top portion  122  and complementary threads  128  on the main container  121 , as is shown in  FIG. 3 . Other similar methods could be used to removably secure the top portion  122  to the main container  121 . 
     Located within the main container  121  is a pump  14 , shown in  FIG. 2 . As shown in  FIG. 2 , the pump is located in the opening  123  of the main container  121 , generally in the neck  124  of the main container. It is also possible that the pump  14  may be located in the top  122  of the reservoir  12 , or located at the bottom of the main container  121 . For the purposes of describing the present invention, the pump will be described as being generally located in the neck  124  of the main container  121 . Generally speaking, the pump  14  has an inlet  141 , an outlet  142  and a recovery means  143 . As with most pumps, the pump  14  has an idle stage, a discharging stage, and a charging stage. In the idle stage, which is shown in  FIG. 2 , the pump  14  mechanism is at rest and is not actively charging or discharging the fluid. The discharging stage of the pump is a stage in which a shot of the fluid is expelled from the pump  14  through the outlet  142  of the pump. In the charging stage of the pump  14 , a shot of the fluid  22  is drawn from the reservoir  12  through the inlet  141  into the pump  14 . The recovery means  143  allow the pump  14  to return to the idle stage from the end of the discharging stage. As the pump  14  is returning to the idle stage from the end of the discharging stage, the pump  14  is in the charging stage. Further details of a pump  14  usable in the present invention will be described below. 
     The suck back mechanism  16  is separate and distinct element from the pump  14 . Generally described, a suck back mechanism  16  usable in the present invention is shown in  FIGS. 5 and 5A  in an exploded view. The suck back mechanism  16  has at least one resilient member  161  capable of storing fluid, a first opening  162  and a second opening  163  (shown in  FIGS. 3 ,  4 ,  5  and  5 A). The resilient member  161  is positioned between the first opening  162  and the second opening  163  of the suck back mechanism  16 . The dispensing end  18  of the dispenser  10  allows the fluid to be dispensed from the dispenser  10  and the dispensing end  18  is connected to the second opening  163  of the suck back mechanism  16 . At the end of the discharging stage of the pump  14 , undispensed fluid remains between the dispensing end  18  and the second opening  163  of the suck back mechanism  16  and a portion of the undispensed fluid is drawn into resilient member  161 , which prevents the undispensed portion from dripping out of the dispensing end  18  and helps prevent stringing of the fluid dispensed to the user with the undispensed fluid. 
     The suck back mechanism  16  may operate independently from the pump  14  or may operate in conjunction with the pump  14 . When operated separately from the pump, the suck back mechanism does not rely upon the recovery means  143  of the pump. When operated in conjunction with the pump, the pump&#39;s recovery means  143  assist recovery of the resilient members during the charging stage of the pump. The first opening  162  of the suck back mechanism  16  is connected to the outlet  142  of the pump  14 . 
     As shown in  FIG. 2 , the dispenser  10  may be provided with a pump mounting element  20 , which is also shown in  FIGS. 3 and 4 . This pump mounting element  20  may be used to hold and/or secure the pump  14  and the suck back mechanism  16  within the dispenser. The pump mounting element  20  fits into the opening  123  of the main container  121 , which is shown in  FIGS. 2 ,  3  and  4  and may be permanently mounted in the opening or removably mounted in the opening. Alternatively, the pump mounting element  20  may be associated with the top portion  122  of the dispenser. That is, the pump mounting element  20  may be removably connected to the top portion  122  of the reservoir. In another alternative configuration, the pump mounting element  20  may be permanently connected with the top portion  122  of the dispenser such that the pump mounting element  20  forms a bottom surface of the top portion  122 . Alternatively, the pump device  12  may be housed within the main container  121 . 
     As is shown in  FIG. 2 , the pump device  14  is located inside the neck  124  of reservoir  12  as described above and serves to draw the fluid or fluid precursor  22  from the main container  121  of the reservoir  12  and force the fluid out the dispensing end  18  of the dispenser  10 . The pump device  14  may be advantageously constructed from widely available “stock” components in order to enhance manufacturing efficiencies. Specifically, pump device  14  is preferably a common lotion pump of the type in widespread use with bottled lotions, shampoos, soaps and the like. Suitable pumps may be purchased from a variety of pump manufactures including, for example Rexam Airspray, Inc., having offices at 3768 Park Central Blvd, North, Pompano Beach, Fla., USA, and Rieke Corporation 500 W.  7th  Street, Auburn, Ind., USA. A suitable commercially available pump is the F2 foaming pump available from Rexam Airspray, Inc. Many other models of foam pumps, lotion pumps are also available on the market, and may be utilized depending on variables such as shot size and the like. As will be explained below, a commercially available pump device may be modified in several ways for use in dispenser  10 , depending on the application or fluid to be dispensed from the dispenser  10 . 
     To gain a better understanding of an exemplary pump that may be used in the present invention, attention is again directed to  FIG. 2 . As shown, pump device  16  is a foaming pump and includes an outer tubular piston  62  and an inner tubular piston  64  located inside of a pump cylinder  66 . As is shown, the pump cylinder  66  has a wide portion  66 W and a narrow portion  66 N. The outer tubular piston  62 , the wide portion  66 W of the pump cylinder  66  and the outer surface of the inner piston  64  form a first chamber  68 , which is an air chamber. The inner piston  64  and the narrow portion  66 N of the pump cylinder  66  form a second chamber  69 , which is the fluid chamber. The pump device  16  further includes a cap element  70 , which is maintained in an axially fixed relation with respect to pump cylinder  66 . Cap element  70  is advantageously used to mount the pump device  16  within reservoir  12 , and as shown, more particularly; to the pump mounting element  20 , which is either contained within the main container  121  or the top portion  122  of reservoir. In the illustrated embodiment, for example, pump mounting element  20  is configured as a disc-shaped member having a threaded portion  76 . The outer threads of threaded portion  76  are engaged by the inner threads of cap element  70 , as shown in  FIG. 2 . Other suitable means may be used to hold the pump assembly  16  in the reservoir  12 . 
     An engaging element  24  is in communication to the pump&#39;s piston assembly  61 . Typically, the engaging element will be physically connected to the piston  61 . In the illustrated embodiment, engaging element  24  is configured having a cylindrical portion  79 , and a disc-shaped flange  80 . It is generally the cylindrical portion  79  which is connected to the piston  61  of the pump  14 . Typically, the engaging element  24  is generally located near the central axis of the reservoir, which provides advantages discussed below. Reciprocative movement of engaging element  24  will cause piston assembly  61  to move within the pump cylinder  66 . Piston assembly  61  is normally urged into an upward position (rest position), shown in  FIG. 2 , due to the force of a pump recovery means  143 . The pump recovery means may be a compressible member or, in an electronic configuration, the motor may be used to recover the pump. Suitable pump recovery means includes a helical spring, as is shown in  FIG. 2 . 
     As is stated above, the pump assembly  14  shown in  FIG. 2  is a foaming pump. The foaming pump shown mixes the liquid  22  from the main container  121  with air within the pump structure. The outer piston  62  contains air inlet openings  72 , which allow air to pass through the outer piston  62  to enter the air chamber  68 . In addition, the outer piston  62  is provided with an air exhaust passage  73 , which allows the air present in the air chamber  68  to escape the air chamber  68 . To prevent air in the air chamber from exiting the air inlet opening  72 , a check valve  74  is positioned near the air inlet opening  72  which opens during the charging stage and closes during the discharging stage of the pump  14 . This check valve  74  also prevent air and/or fluid from entering the air chamber  68  during the charging stage from the air exhaust passage  73  during the charging stage of the pump. Operation of this check valve is described in more detail in U.S. Pat. No. 5,443,569 to Uehira et al., which is hereby incorporated by reference. 
     Pump device  16  is further provided with additional check valves  84 ,  85  and  86  to ensure proper flow of the liquid through the pump. Check valve  86 , located at the base of pump cylinder  66 , allows the liquid  22  to be drawn into a lower liquid chamber  69 , through the inlet  141  of the pump when inner piston  64  moves in an upward direction (charging stage). When inner piston  64  moves in a downward direction (discharging stage), check valve,  85  allows the liquid  22  to be passed into an upper liquid chamber  90  from the lower liquid chamber  69 . In addition, check valve  84  allow fluid to exit the upper pump chamber  90  into the mixing chamber  92 . Both check valves  84  and  85  are opened at the same time and close at the same time. In the mixing chamber  92 , air from the air chamber  68  is mixed with the liquid  22  from the upper liquid chamber  90 . The mixing of the air and liquid creates a foam fluid which is forced through a porous member  93 . The porous member  93  is in the form of a porous net or screen-like structure to create uniformity in the foam bubbles of the fluid. The fluid is then force through the outlet  142  of the pump  14 . 
     While a variety of different check valve configurations are contemplated, the illustrated embodiment utilizes common ball and seat valves. Other configuration of these elements may be used without departing from the scope of the present invention. Other structures and functional elements, such as seals and gaskets may be used in the pump device to the pump form leaking or improve the function of the pump. Further it is noted that the pump assembly  14  described above is a foaming pump and that non-foaming pumps may also be used in the present invention. Non-foaming pumps work much in the same manner as the foaming pump described above, but are devoid of outer piston, air chamber, air inlet and mixing chamber described above. The liquid is passed through the pump in the same manner as the foaming pump but is not mixed with air prior to leaving the pump outlet  142 . 
     Referring to  FIGS. 2 ,  3  and  4 , the fluid leaving the outlet  142  of the pump  14  is transported to the suck back mechanism  16 . Generally, the outlet  142  of the pump  14  typically moves with the piston assembly  61 . To counter act this movement, the outlet  142  of the pump  14  is joined to the first opening  162  of the suck back mechanism  16  with a flexible tube  96 . The flexible tube  96  has a first end  97  attached to the outlet  142  of the pump and a second end  98  attached to the first opening  162  of the suck back mechanism  16 . By connecting the outlet  142  of the pump  14  with the suck back mechanism  16  with the flexible tube, the suck back mechanism  16  can be mounted to the pump mounting member  20  in a stationary manner, which will improve the operation of the suck back mechanism  16  during use. As is shown in  FIG. 2 , the suck back mechanism  16  is mounted on a mount  179 . 
     Attention is directed to  FIGS. 5 and 5A , which each show a configuration usable for the suck back mechanism. As is stated above, the suck back mechanism  16  is provided with a first opening  162 , which functions as an inlet for the fluid being pumped from the pump  14  into the suck back mechanism  16 . The suck back mechanism  16  also has a second opening  163 , which functions as an outlet from the suck back mechanism  16  when the pump  14  is in the discharging stage. The second opening  163  also functions as an inlet for a portion of any undispensed fluid between the suck back mechanism  16  and the dispensing end  18  of the dispenser, when the pump  14  is in a charging stage. The suck back mechanism  16  also has at least one resilient member  161 , which is capable of drawing a portion of any undispensed fluid between the second opening  162  of the suck back mechanism  16  and the dispensing end  18  into resilient member  161 . The function of the resilient member may be independent of the recovery means  143  of the pump  14  or may be aided by the recovery means  143  of the pump  14 . 
     Generally, there are one or more resilient members  161  in the suck back mechanism. The resilient member(s)  161  are shaped and are prepared from a material which allow the resilient member(s) to be compressed and recover to essentially it same size and shape. Exemplary shapes for the resilient member  161  are shown in  FIGS. 7 and 8 .  FIG. 7  shows a corrugated bellows shape and  FIG. 8  shows a resilient member having a truncated cone shape. The resilient member is prepared from an elastomeric material, including for example, natural rubber, a silicone rubber, or any other material which is elastomeric in nature. Alternatively, other resilient materials may be used, so long as the material is capable of recovering from a compressed state. The actual size of the resilient members can be selected by those skilled in the art to create the ideal suction force needed to allow the resilient members to effectively intake the fluid and/or create a desire level of vacuum to effectively draw the fluid into the suck back mechanism. Generally, higher viscosity fluids will require a larger volume in the hollow portions of the resilient members. 
     In one embodiment is shown in  FIG. 5 , a plurality of resilient members  161  are used in the suck back mechanism  16 . Specifically, two resilient members  161  are shown. As shown, the suck back mechanism  16  has a lower member  164  and an upper member  165 , which is joined to the lower member  164 . The upper member  165  and the lower member  164  should form an air tight seal when joined together. Additional seals or sealing materials may be used to ensure that combination of the upper and lower members  165  and  164  are air tight. Such seals and sealing members would readily be apparent to those skilled in the art. The upper member  164  has a seat  168  which adapted to create a seal with the resilient members  161 . The resilient members  161  may be held in place on the seat  168  with a retainer  166  or any other suitable means to maintain an air tight seal in the suck back mechanism. Typically, the retainer  166  will snap into place onto the upper member  165  to securely hold the resilient members in place during use. Again, the resilient members  161  should create an air tight seal with the upper member  165 . If the suck back mechanism  16  does not have an air tight seal, the suck back mechanism  16  may not operate in a proper manner. 
     In addition to forming an air tight seal, in one embodiment of the present invention, the upper member  164  and lower member  165 , when joined together, should create a channel or passage  174 . This channel or passage  174  connects the primary fluid passageway  175  through the suck back mechanism  16  to the resilient members  161  and the hollow portion  173  of the resilient member  161 , thereby allowing the suck back mechanism to draw a portion of the undispensed fluid into the hollow portion  173  of the resilient members  161 . This channel or passage  174  also allows the portion of the undispensed fluid drawn into the hollow portion  173  to exit the hollow portion  173  of the resilient member  161  to be placed back into the primary fluid passageway  175 . 
     In an alternative configuration, a single resilient member  161  may be used in the suck back mechanism  16 . When a resilient member  161  is used, it can be formed using a structure shown in  FIG. 5 , where one of the resilient members is removed and the retainer  166  holds a cap (not shown) or creates a seal with seat  168 . Alternatively, a structure similar to that shown in  FIG. 5A  may be used for the suck back mechanism  16 , when a single resilient member  161  is used. As is shown in  FIG. 5A , the suck back mechanism  16  has an inlet  162 , and an outlet  163 . A passageway  171  is created between the inlet  162  and the outlet  163  and the passageway as vents  170 , which allow the fluid to pass from the passageway into the resilient member  161 . The resilient member  161  should create a seal with the passageway  171  to ensure that the suck back mechanism will operate properly. Other similar structures may be used in the present invention as the suck back mechanism, provided that the structures allow undispensed fluid between the pump and the dispensing end of the dispenser.  FIG. 6  is similar to  FIG. 3  described herein, except  FIG. 6  shows a suck back mechanism of  FIG. 5A  in use on the reservoir  12 . 
     Generally, the suck back mechanism  16  may be held in the pump mounting element  20  with a suitable mounting means. For example, the suck back mechanism  16  would be provided with mounting structure  167  on the upper member  165  of the suck back mechanism. The mounting structure could be a hole or protrusion which would allow the suck back mechanism  16  to be mounted on a mount  179 , which is present on the pump mounting structure  20 . The suck back mechanism  16  could be adhered to the mount  179  using an adhesive, or the suck back mechanism  16  could be mechanically attached to the mount  179  using a mechanical mounting means, such as a screw. Any other mechanical mounting means may be used so long as the suck back mechanism  16  is stationary within the pump mounting element  20 . 
     As is shown in  FIG. 2 , the resilient member  161  is generally hollow structures having an opening  172  located near the portion of resilient member  161  which is to be positioned at or near the seat  168 . The hollow portion  173  of the hollow structure allows the resilient member  161  to store the fluid. In addition, the hollow structure of the resilient member is allowed to collapse, thereby forcing the fluid within the reservoir out of the reservoir. As the resilient member  161  returns to its original shape and size, a vacuum is created by the hollow portion  173 , which causes the fluid to be refilled in the resilient member. 
     The fluid exits the suck back mechanism  16  at the second opening  163  and the fluid exits the dispenser  10  through the dispensing end  18  of the dispenser. The dispensing end  18  may be located at a distal end  19 D of a tube  19  which is connected to the second opening  163  of the suck back mechanism  16  at a proximate end  19 P of the tube  19 . This is shown in  FIGS. 1 and 2 . In an alternative embodiment, the dispensing end  18  may be in the form of a nozzle (not shown in the drawings). Generally, when the tube  19  is present, the tube  19  prepared form a flexible material. 
     Additional elements which may be present in the dispenser  10  of the present invention include an actuator  26 , and an actuator rod  30 . The actuator  26  is operable connected to the outer piston  62  of the pump  14 , as is shown in  FIG. 2 . The actuator serves to activate the pump  14 , causing the pump to move from a resting stage, shown in  FIG. 2 , to a discharging stage, moving liquid from the reservoir  12  through the pump  14 , suck back mechanism  16  and out of the dispensing end  18  of the dispenser  10 . As is shown in  FIG. 2 , the actuator  26  has a upper structure  27  and a lower structure  28 . The upper structure  27  is joined to the lower structure  28  with a connecting side structure  29 . Generally there are more than one side structures  29  present in a single actuator  26 , so that the upper structure  27  of the actuator and the lower structure  28  work in unison as a single unit. The structure of an actuator usable in the present invention can be further seen in  FIGS. 3 and 6 . One further element that may be present in a filling port  23 , which allows the reservoir  12  to be filed with the fluid. 
     As can be seen in  FIGS. 2 ,  3  and  6 , a lower surface  31  of the upper actuator structure  27  may contact the resilient members  161 . By having the actuator  26  contact the resilient member  161 , as the actuator is moved from its rest position, as shown in  FIGS. 2 ,  3  and  6  to its depressed position, shown in  FIG. 2 , the lower surface  31  of the actuator&#39;s upper structure compresses the resilient members  161 , thereby forcing the fluid present hollow portion from the resilient member  161  into the channel  175  and subsequently out of the dispensing end  18  of the dispenser. The lower surface  31  of the actuator&#39;s upper structure  27  may merely contact the resilient member  161  or may be physically joined to the resilient members. Suitable method of joining the lower surface  31  to the resilient member  161  includes, for example, adhesive means, mechanical means or a combination of adhesive and mechanical means. Having the resilient member  161  joined to the lower surface  31  has the advantage that the pump recovery means  143  can be used to assist the resilient member  161  in recovering to its starting shape and size, creating a vacuum to draw the fluid from the dispensing end  18  back towards the suck back mechanism  16 . However, it is not necessary to have the resilient member  131  connected to the lower surface  31  of the upper actuator structure  27 . 
     To activate the actuator  26  to dispense the fluid from the dispenser  10 , an actuator rod  30  contacts the top surface  32  of the actuator, as is shown in  FIG. 2 . Alternatively, the actuator rod may be connected to the top surface  32  of the actuator  26 . The actuator rod  30  may contact the top surface  32  of the actuator  26  by passing though an actuator opening  130 , shown in  FIGS. 1 and 3 , located in the top portion  122  of the reservoir assembly  12 . The actuator opening  130 , is generally positioned about the center line of the top portion  122 . In one embodiment of the present invention, the tube  19 , connecting the dispensing end  18  to the second opening  163  of the suck back mechanism  16 , will be centrally located in the actuator opening  130 , as is shown in  FIG. 1 . The actuator opening  130  may be a single opening such that the actuator rod  30  can come into contact with top surface  32  of the actuator  26 . 
     As the actuator rod  30  depresses the actuator  26 , the actuator  26  depresses the resilient members  161  and depresses the outer tubular piston  62  and an inner tubular piston  64  of the pump, transitioning the pump  14  from the rest stage to the discharging stage. Depressing the resilient members  161  causes any fluid within the hollow portion  173  to be expelled from the resilient members  161  into the primary fluid passageway  175  and towards the dispensing end  18  of the dispenser. In addition, fluid is expelled from the pump  14  through the outlet  142  of the pump into the flexible tube  96 , which carries the fluid to the suck back mechanism  16 . The fluid enters the primary passage  175  of the suck back mechanism  16  and joins the fluid expelled from the resilient member  161 . The fluid is also expelled from the dispensing end  18  of the dispenser  10 . At the end of the actuator&#39;s  26  depressing the resilient member  161  and the pistons of the pump, the pump recovery means  143  causes the pump to transition from the discharging stage to the charging stage. During the charging stage of the pump  14 , the actuator  26  is returned to its rest position, shown in  FIG. 2 , which in turn allows the resilient member  161  to return to its original shape from a compressed state. As the resilient member  161  is returned to its original shape, a vacuum is created, causing a portion of any undispensed fluid between the suck back mechanism  16  and the dispensing end  18  to be drawn back into the resilient member  161 . It is this vacuum created and the drawing of the portion of the undispensed fluid into the resilient member  161 , prevents the problems of stringing and dripping from the dispensing end  18  of the dispenser. 
     The dispenser  10  of the present invention may be used as an under-counter dispenser, such as the one shown in  FIG. 9 . When used as an under-counter dispenser, the actuator rod  30  may be manually activated by a user, by having the end of the actuator rod  30  opposite the actuator operably connected or in contact with an actuation button  222 . As the actuation button  222  is depressed by the user, the actuator rod depresses the actuator  26 , which in turns activates the pump  14  and suck back mechanism  16  as stated above. Typically, the actuator button  222  is located on a dispensing head  220 . The dispensing head  220  also has a delivery spout  224 . Holding the dispensing head  220  to the counter (not shown) is a anchoring mechanism  228 , which is associated with a portion of a generally hollow elongated tube  226  which extends below the counter. In the hollow portion of the elongated tube  226  is the actuator rod  30 . At the end of the elongated tube  226  opposite the dispensing head  220  is a connecting member  230 . The dispenser has complementary connecting members  40  located on the dispenser  10 , which serve to connect the dispenser to the dispensing head  220  and/or the elongated tube. In this configuration, the tube  19  is inserted through the connecting member  230 , through the elongated tube  228  and into the delivery spout  224  so that the dispensing end is at or near the end  221 ′ of the delivery spout. In the configuration shown in  FIG. 9 , the dispenser is manually operated by the user. 
     In an alternative embodiment of the present invention, the pump  14  and suck back mechanism  16  is electronically activated. An example of an electronic viscous liquid dispensing system is shown in  FIG. 10 . An electronically activated pump may operate in many different ways. One way is to have a user push an actuation button  222  located on or near the dispensing head or to provide a sensor  223  which would detect the users hands under the spout  20 . When used as an electronic activation of the pump, the actuation button may be a push button, a sensor or any other means known to those skilled in the art to electronically activate the pump. 
     As can be seen in  FIG. 10 , the electronic viscous liquid dispensing system has a dispensing head  220 , and elongated tube  226 , a motor housing  202 , a power pack housing  204 , a connecting member  230  and a reservoir assembly  12 . Essentially the components are similar or are the same as described above with the exception that the motor housing  202  is positioned between the elongated tube  226  and the connecting member  230 . In addition the power pack housing  204  contains a power supply which is electrically connected to a motor. The dispensing head  220  has an actuator button  222 , and/or a sensor  223  which is used to activate a motor which engages the pump  14  by the actuator rod  30  and the actuator. The actuator button  222  and/or the sensor  223  are electrically connected to the motor. Generally, the actuator button  222  and/or the sensor  223  are electrically connected to a control panel (not shown) having control circuitry which is used to detect a user&#39;s hand near under the spout  224 , or the user&#39;s input to the actuator button  222 . In addition, the control circuitry is used to activate the motor for a given period of time so that the user receives a dose of the viscous liquid. Control circuitry for sensors and buttons is known to those skilled in the art and is shown, for example in U.S. Pat. No. 6,929,150 to Muderlak et al., which is hereby incorporated by reference. 
     In the electronic viscous liquid dispensing system, the connecting member  230  may be connected to the motor housing  202  and power supply housing  204 . Alternatively, the motor housing  202  may be integral with the connecting member  230 , meaning that the motor housing  202  and connecting member  230  are a single unit. Typically, the power supply  204  may be separated from the motor housing so that the power supply may be replaced when needed. That is, the power supply is disconnectable and reconnectable to the motor housing. To ensure that power is transferable from the power supply  204  to the motor housing, electrical contact points may be used on both the motor housing and power supply, such that the electrical contact points are in complementary positions, meaning that when power supply is attached to the motor housing an electrical connection is made. 
     To gain a better understanding of a possible configuration of the motor housing  202 , attention is now directed to  FIGS. 11A , B, C and D. The motor housing  202  houses a motor  210 , gears  211 ,  212  which are engaged with motor  210  and an additional gear  213  which drives an actuator rod  30 . The motor driven actuator rod  30  is housed in the motor housing  202  and extends from the motor housing  202  through an opening present in the lower surface of the connecting member  230 . Any method may be used to drive the motor driven actuator rod  30 . In a typical operation of the electronic viscous liquid dispensing system, the motor driven actuator rod  30  contacts the actuator  26  and pushes the actuator downward to activate the pump  14  one or more times to expel a dose of the viscous liquid from the spout  224  of the dispensing head  220 . 
     Numerous ways may be used to transfer power from an activated motor to the motor driven actuator rod  30 . For example, the motor may drive a series of wheels, gears or other energy transmission means to the actuator rod  30  which extends and contacts the actuator  26 . In one embodiment of the present invention, which is intended to be an exemplary means that may be used to drive the actuator rod  30 , the drive wheel  213  has a post or shaft  214  extending from one area of the gear body near the periphery  215 , as is shown if  FIG. 11A and 11B . As the motor  210  turns the motor drive wheel  211 , the motor drive wheel  211  in turn rotates one of more wheels  212 . In  FIG. 11A , a single wheel  212  is shown; however, it may be desirable to have more wheels to reduce the rotational speed of the actuator drive wheel  213 , so the pump is activated in a controlled manner. It is within the skill of those skilled in the art to select the ratio of drive wheel so that the appropriate speed is achieved of the actuator drive wheel  213 . It is noted the term “wheel”, as used herein is intended to cover any wheel like mechanism, including wheels per se and other wheel-like mechanisms such as gears. Generally, gears are desirable, since gears are less likely to slip during use. 
     As is shown in  FIG. 11B , the actuator drive wheel  213  has a shaft  214  extending from a non-central area of the actuator drive wheel  213 , which makes the shaft rise and lower in the direction  325  as the actuator drive wheel  213  turns. This shaft  214  is fitted into a horizontal channel  322  present in the actuator guide member  320 . The horizontal channel  322  is generally in the horizontal axis  2 . The horizontal channel  322  is created by two horizontal protrusions  321  and  321 ′ extending from one of the sides of the actuator guide member  320 . As the actuator drive wheel turns, the shaft  214  travels in a circular path and has a vertical movement  325  in the vertical axis  1 , shown in  FIG. 11B  and a horizontal movement  326  in the horizontal axis  2 , shown in  FIG. 11C . The vertical movement  325  of the shaft  214  causes the actuator guide member  320  to move up and down in the vertical axis  1 , which in turn moves causes the motor driven actuator rod  30  to also move in an up and down manner in the vertical axis. Below the channel  322  present on the actuator guide member  320  is the actuator rod  30 . The actuator guide member  320  is held in place so that the movement of the actuator guide member is in an up and down manner in the vertical axis and not side to side or front to back. The actuator guide member  320  may be held in place, for example by providing vertical guide slots  323  so that the lateral sides of the actuator guide member  320  are held in place on the horizontal axis. These vertical guide slots  323  maybe provided in the motor housing  202  as is shown in  FIGS. 11B ,  11 C and  11 D. 
     As is mentioned above, the shaft  214  also has a horizontal movement  326  in the horizontal axis  2 . This horizontal movement is essentially unwanted. To account for the horizontal movement, the shaft is allowed to move horizontally in the horizontal axis  2  along the channel  322  in the actuator guide member. Therefore, the channel  322  controls the essentially unwanted horizontal movement  326  of the shaft  214 . 
     The electrical powered viscous liquid dispensing systems may also have additional features. For example, dispensing head  220  may have indicator lights to signal various events, such as, recognition of a user, low battery, empty soap reservoir, or other conditions such as a motor failure. Examples of such lights include low power consumption lights, such as LED (light emitting diodes). 
     The power source for the electronic viscous liquid dispensing system of the present invention may include disposable DC batteries (not shown). Alternatively, the power supply may be a closed system which requires that the entire power supply be replaced as a single unit. Although not shown in the figures, an AC to DC adapter may be utilized to provide an alternate source of power to the viscous liquid dispenser. This embodiment may be particularly useful wherein the viscous liquid dispenser is mounted in close proximity to an AC outlet or when it is desirable to power multiple dispensers from a centrally located transformer of suitable configuration and power. The number of batteries used to power the motor will depend on the motor selected for the dispenser. Disposable batteries usable in the present invention include 9 volt batteries, 1.5 volt batteries, such as D-cell or C-cell batteries, or other similar batteries. The exact type of battery selected for use is not critical to the present invention so long as the power supplied to the motor is compatible for the motor. For applications where the viscous liquid dispenser will be used under low usage situations, rechargeable batteries could be used. If the dispenser is to be used in a bright light situation, the batteries could be solar rechargeable batteries. 
     Although the present invention has been described with reference to various embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. As such, it is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is the appended claims, including all equivalents thereof, which are intended to define the scope of the invention.