Patent Publication Number: US-9408502-B2

Title: Fluid dispensers with increased mechanical advantage

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. application Ser. No. 13/768,110, filed on Feb. 15, 2013, entitled, “FLUID DISPENSERS WITH INCREASED MECHANICAL ADVANTAGE,” which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The disclosure relates to fluid dispensers. 
     BACKGROUND 
     Hand washing is important in many industries, including hospitality (hotels, restaurants, etc.) and healthcare (hospitals, nursing homes, etc.). In addition, there are many other applications in which the dispensing of various fluids occurs. To facilitate hand washing, for example, fluid dispensers that dispense hand cleansing products may be placed near sinks of a kitchen, washroom, or other location. Such fluid dispensers house a disposable or refillable product container, such as a cartridge or flexible bag, containing a supply of the fluid product to be dispensed. The fluid may include, for example, foams, liquids, and/or gels. The dispensers are generally wall mounted and include a hinged cover which permits opening and closing of the dispenser housing so that the supply of fluid product may be refilled or replaced. Some fluid dispensers are manually actuated by pushing or pulling a handle, bar, or button on the dispenser. Others dispense automatically by sensing presence of a user or the user&#39;s hands near the dispenser. 
     SUMMARY 
     In general the disclosure is directed to fluid dispensers and fluid dispense mechanisms providing increased mechanical advantage as the dispense mechanism is moved throughout its range of motion. 
     In one example, the disclosure is directed to a dispenser comprising a housing, a reservoir positioned in the housing that contains a supply of a fluid to be dispensed, and a dispense mechanism configured to dispense a discrete quantity of the fluid from the reservoir, the dispense mechanism comprising a lever member having a first lever section accessible on an exterior side of the housing, a second lever section, and a fulcrum connected between the first lever section and the second lever section, the fulcrum pivotally supported within the housing such that the lever member is moveable between a rest position and a dispense position upon application of an input force to the first lever section, wherein movement of the lever member between the rest position and the dispense position results in application of an output force by the second lever section, and an actuator configured to receive application of the output force from the second lever section, a pump configured to receive the output force from the actuator and apply a corresponding dispensing force to the reservoir to dispense the discrete quantity of fluid from the reservoir, the second lever section configured to provide at least two contacts points with the actuator as the lever member is moved from the rest position to the dispense position, the second lever section comprising a base segment connected to the fulcrum and providing a first contact point with the actuator and a branch segment connected distally adjacent to the base segment and providing a second contact points with the actuator, the base segment having a thickness that is relatively greater than a thickness of the branch segment, such that a mechanical advantage provided at the first contact point is relatively greater than a mechanical advantage provided at a second contact point, such that an output force applied to the actuator at the first contact point is relatively greater than an output force applied to the actuator at the second contact point. 
     The drive length of the first contact point may be relatively shorter than a drive length provided by the second contact point. The base segment of the second lever section may apply the output force to the actuator during a first portion of a dispensing stroke and the branch segment of the second lever section may apply the output force to the actuator during a second portion of the dispensing stroke. The fluid product may comprise one of a liquid, a gel, or a foam. The lever member may comprise one of a push bar, a push button, or a handle. 
     The details of one or more examples are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a perspective view of an example fluid dispenser that provides increased mechanical advantage. 
         FIG. 1B  is a front perspective view of the example fluid dispenser of  FIG. 1A  with the cover removed. 
         FIG. 1C  is a front perspective view of the example fluid dispenser of  FIGS. 1A and 1B ) with the cover and the push bar removed. 
         FIGS. 2A and 2B  are simplified perspective views of an example prior art dispense mechanism for a fluid dispenser. 
         FIGS. 3A-3C  show simplified side views of an example dispense mechanism in accordance with the present disclosure. 
         FIG. 4  shows a simplified side view of another example dispense mechanism in accordance with the present disclosure. 
         FIGS. 5A and 5B  show simplified side views of another example dispense mechanism in accordance with the present disclosure. 
         FIGS. 6A-6C  show simplified side views of another example dispense mechanism in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In general the disclosure is directed to fluid dispensers and fluid dispense mechanisms providing increased mechanical advantage as the dispense mechanism is moved throughout its range of motion. Dispensing of fluid products, such as liquids, gels, foams, etc., is becoming increasingly difficult due to the demand for fluid products having increased concentration, thickness, and quality. These product properties result in a product that is more difficult to dispense, and thus require more force to actuate the dispensing pump. However, dispenser manufacturers must at the same time comply with the Americans with Disabilities Act (ADA), which states that the force required to activate the controls of a hand soap dispenser in places of public accommodation or commercial facilities shall be no greater than 5 lbf (pounds of force). 
       FIG. 1A  is a front perspective view of an example fluid dispenser  100  that provides increased mechanical advantage in accordance with the present disclosure.  FIG. 1B  is a front perspective view of the example fluid dispenser  100  of  FIG. 1A  with the cover removed.  FIG. 1C  is a front perspective view of the example fluid dispenser  100  of  FIGS. 1A and 1B ) with both the cover and the push bar removed. 
     Example dispenser  100  includes a housing  110  having a front cover  102  and a back plate  104 . A reservoir  112  (see  FIGS. 1B and 1C ) located within the interior of the housing  110  contains a supply of the fluid to be dispensed. Back plate  104  facilitates mounting of dispenser  100  to a wall or other object. In this example, housing  110  may include a hinge or hinges which permit cover  102  to pivot between a closed position and an open position. A button or latch  106  may be depressed to unlatch cover  102 , thus permitting cover  102  to be opened and closed. A lever member  120 , in this example a so-called push bar, manually operable by a user, is externally accessible on the outside of dispenser housing  110 . Push bar  120  forms a part of a dispense mechanism, the other portions of which are physically located within the interior of housing  110  when the dispenser is fully assembled and the cover is closed, as shown in  FIGS. 1B and 1C . Although for purposes of illustration the concepts of the present disclosure are generally described herein with reference to a push bar as the user actuatable lever member, it shall be understood that any other type of manually actuatable component, such as a push button, push or pull handle, or other type of lever configuration, may be substituted for the push bar, and that the disclosure is not limited in this respect. 
     As shown in  FIGS. 1B and 1C , push bar  120  further includes a hinge  118 . To incorporate push bar  120  into dispenser  100 , hinge  118  may be pivotally mounted to the inside of the dispenser housing  110  or otherwise pivotally supported within the dispenser  100 . Push bar  120 , when depressed by a user, pivots around hinge  118  through a range of motion from a rest position to a dispense position. In this example, the rest position is the position of the push bar when no force is applied and the dispense position is the fully depressed position at which a metered dose of fluid is dispensed. 
     In addition to push bar  120 , the dispense mechanism of dispenser  100  further includes an actuator  116 . Application of an input force to push bar  120  results in a corresponding application of an output force to actuator  116 . In response to application of the output force, actuator mechanically activates a pump  114  resulting in dispensation of the discrete quantity of the fluid  108  from reservoir  112 . 
       FIGS. 2A and 2B  are simplified views of an example prior art dispense mechanism  150  for a fluid dispenser. Housing  110 , back plate  104 , etc. are not shown for purposes of illustration. Dispense mechanism  150  includes a push bar  151 , an actuator  156 , and a pump  158 . Push bar  151  generally operates in accordance with the principles of a lever. Push bar  151  includes a first lever section  152  and a second lever section  154  which pivot about an axis of rotation or fulcrum provided by a hinge or other pivot point  157 . Hinge  157  may be substantially fixedly received into corresponding recesses or other attachment points located within the interior side of the dispenser housing. Application of an input force by a user to first lever section  152  in the direction indicated by arrow  162  causes push bar  151  to pivot on the axis provided by hinge  157 . This results in a corresponding rotational movement of second lever section  154  and application of an output force to actuator  156 , and thus to pump  158 , in the direction of arrow  164 . The output force applied to the lower surface of actuator  156  by the push bar in  FIGS. 2A and 2B  is focused at one contact point; namely, the distal end  160  of second lever section  154 . 
     The ratio of the output force (F B ) to the input force (F A ), or mechanical advantage (MA), may be used as a measure of the force amplification of a lever. The concept of mechanical advantage may be applied to a push bar of a fluid dispenser, such as push bar  150  shown in  FIGS. 2A and 2B . For example, the MA of push bar  151  may be expressed in terms of the input force, F A , applied to the first lever section as indicated by arrow  162  and the output force, F B , applied by the second lever section  154  to the actuator  156 , as indicated by arrow  164 . This ratio in turn is proportional to the ratio of the length, a, of the first lever section  152  and the length, b, of the second lever section  154  from a fulcrum or hinge  157 : 
             MA   =         F   B       F   A       =       a   b     .             
In this example, the output force F B  and thus the mechanical advantage provided by the push bar in  FIGS. 2A and 2B  is focused at one contact point; namely, the distal end  160  of second lever section  154 . Thus, the length of the second lever section  154  for purposes of calculating the mechanical advantage in this example is equal to the total length b of the second lever section  154 .
 
       FIGS. 3A-3C  show simplified side views of an example dispense mechanism  201  in accordance with the present disclosure. Dispense mechanism  201  includes a push bar  200 , an actuator  210 , and a pump  208 . Push bar  200  includes a first lever section  202 , a second lever section  204 , and a hinge  206 . First lever section  202  has a total length, a, and second lever section  204  has a total length, b. Actuator  210  is configured to allow for two points of contact with push bar  200 . To that end, example actuator  210  includes a first contact surface  212  configured to contact second lever section  204  at a first contact point and a second contact surface  214  configured to contact second lever  204  section at a second contact point. The first contact point is indicated generally by reference numeral  215  and is located somewhere between the hinge  206  and the distal end  216  of second lever section  204 . The second contact point is generally indicated by reference numeral  217  and is located at the distal end  216  of second lever section  204  in this example. 
     In operation, application of a force by a user to first lever section  202  in a direction generally indicated by arrow  203  causes push bar  200  to pivot on the axis provided by hinge  206 . As shown in  FIG. 3B , second lever section  204  first contacts and applies a force to first contact surface  212  at first contact point  215  located between hinge  206  and distal end  216  of second lever section  204 . The distance between contact point  215  and hinge  206  is indicated by a length c. The drive length of the lever section to which the input force is applied at the beginning of dispenser operation is thus approximately equivalent to the distance c. It shall be understood that the distance c will vary somewhat as the push bar rotates about hinge  206 ; however, the drive length c will always be relatively shorter than the total length b of the section lever section  204  in this example. 
     Referring now to  FIG. 3C , as push bar  200  continues to rotate about hinge  206 , the second contact point  217  at distal end  216  of second lever section  204  contacts second contact surface  214  of actuator  210 . The drive length of the lever section to which the input force is applied thus transitions from the relatively short drive length c to a relatively longer relative drive length given by b. 
     The mechanical advantage provided by the relatively shorter drive length, MA short , in this example may be defined by: 
     
       
         
           
             
               MA 
               short 
             
             = 
             
               
                 a 
                 c 
               
               = 
               
                 
                   F 
                   C 
                 
                 
                   F 
                   A 
                 
               
             
           
         
       
     
     The mechanical advantage provided by the relatively longer drive length, MA long , in this example may be defined by: 
     
       
         
           
             
               MA 
               long 
             
             = 
             
               
                 a 
                 b 
               
               = 
               
                 
                   F 
                   B 
                 
                 
                   F 
                   A 
                 
               
             
           
         
       
     
     Because push bar  200  first contacts actuator  210  with the short drive length, c, the mechanical advantage applied at the beginning of the dispenser operation is relatively higher than the mechanical advantage applied toward the end of the dispenser operation. This allows the pump to start dispensing with a relatively smaller amount of input force required from the user. 
     As push bar  200  rotates about hinge  206 , actuator  210  is contacted by long drive length, b, and the MA is decreased as compared to the short drive length, c. In addition, the longer drive length defined by the length b reduces the angle, indicated by reference numeral  207 , through which push bar  200  must travel to completely depress the pump. This may help to keep push bar  202  clear of the discharge spray  218 , as shown in  FIG. 3C . If only the short drive length c were used then the push bar may interfere with the pump spray, because the degree of rotation required to fully depress the push bar and to fully dispense the product may be increased. 
       FIG. 4  shows a simplified side view of another example dispense mechanism  221  in accordance with the present disclosure. Dispense mechanism  221  includes a push bar  220 , an actuator  230  and a pump  235  in accordance with the present disclosure. Push bar  220  includes a first lever section  222 , a second lever section  224  and a hinge  226 . First lever section  222  has a total length, a, and second lever section  224  has a total length, b. In this example, actuator  230  is configured to have three contact surfaces; a first contact surface  232 , a second contact surface  234 , and a third contact surface  236 . In operation, second lever section  234  contacts first contact surface  222 , second contact surface  224 , and third contact surface  226  at drive lengths d, c, and b, respectively, throughout the rotation of push bar  220 . Thus, as the push bar is moved through its range of motion, the mechanical advantage provided upon initial application of a dispensing force (MA d  provided by drive length d at contact surface  232 ) is relatively larger than that provided during the middle of the stroke (MA c  provided by drive length c at contact surface  234 ), which itself is relatively larger than that provided toward the end of the stroke (MA b  provided by drive length b at contact surface  236 ). This relationship may be expressed by the following equation:
 
 MA   d   ≧MA   c   ≧MA   b .
 
       FIGS. 5A and 5B  show simplified side views of another example dispense mechanism  241  in accordance with the present disclosure. Dispense mechanism  241  includes a push bar  240 , an actuator  250  and a pump  251  in accordance with the present disclosure. Push bar  240  includes a first lever section  242 , a second lever section  244  and a hinge  246 . In this example, actuator  240  includes a curved contact surface  252 . As push bar  240  rotates through its range of motion, surface  252  provides a continuously varying point of contact with the second lever section  244 . The point of contact varies between a first contact point  243  at a drive length c located between hinge  246  and distal end  248  of second lever section  244  and a second contact point  245  at a drive length b located at the distal end of second lever section  244 . Curved contact surface  252  may provide a smooth transition of contact along at least a portion of second lever section  244  of push bar  240 , which may help provide a smoother user experience during operation of the dispenser. The angle of rotation  247  at full depression of push bar  240  is sufficiently small to avoid interference with fluid discharge stream  249 . 
     Because push bar  240  first contacts actuator  250  with the short drive length, c, the mechanical advantage applied at the beginning of the dispenser operation is relatively higher than the mechanical advantage applied toward the end of the dispenser operation, when push bar  240  is contacting actuator  250  with the relatively longer drive length b. 
       FIGS. 6A-6C  show simplified side views of another example dispense mechanism  261  in accordance with the present disclosure. Dispense mechanism  261  includes a push bar  260 , an actuator  270 , and a pump  280  in accordance with the present disclosure. In this example, push bar  260  is configured to provide two points of contact with actuator  270 . Push bar  260  includes a first lever section  262 , a second lever section  264 , and a hinge  266  connected between the first lever section  262  and the second lever section  264 . Actuator  270  includes a contact surface  272 . Second lever section  264  includes a base segment  292  connected to the hinge  266  and providing a first contact point  265  and a branch segment  294  connected distally adjacent to the base segment  292  and providing a second contact point  267 . In this example, to provide for multiple contact points, base segment  292  and branch segment  294  are of differing thicknesses to provide first and second contact points  265  and  267 , respectively. In this example, the thickness, i, of base segment  292  is relatively greater than the thickness, j, of branch segment  294 . 
     In operation, second lever section  264  first applies an output force upon contact surface  272  at the relatively shorter drive length c. Then, as the rotation of push bar  260  continues, application of the force transitions to the relatively longer drive length b. Thus, as push bar  260  is moved through its range of motion, the mechanical advantage provided upon initial application of a dispensing force (MA c  provided by drive length c by contact point  265 ) is relatively larger than the mechanical advantage provided during the latter portion of the stroke (MA b  provided by drive length b by contact point  267 ). This relationship may be expressed by the following equation:
 
 MA   c   ≧MA   b .
 
     Because push bar  260  first contacts actuator  270  with the short drive length, c, the mechanical advantage applied at the beginning of the dispenser operation is relatively higher than the mechanical advantage applied during the latter portion of the dispenser operation, when push bar  260  is contacting actuator  270  with the relatively longer drive length b. 
     Alternatively, push bar  260  may be configured to provide multiple points of contact. For example, second lever section  264  may include a base segment, such as base segment  292 , connected to hinge  266  and providing a first contact point  265 . Second lever section  264  may further include one or more branch segments connected distally adjacent to the base segment  261  and providing a corresponding one or more contact points. In this example, to provide for multiple contact points, the base segment and each of the one or more branch segments may have differing thicknesses to provide the multiple contact points. For example, each branch segment may have a relatively smaller thickness than the proximally adjacent branch segment. 
     Although specific example fluid dispensers are shown and described herein that provide for multiple points of contact during dispenser operation, it shall be understood that many other variations of the fluid dispensing mechanism may also be used without departing from the spirit and scope of the present disclosure. For example, the actuator and/or the push bar may be configured in a variety of different ways to provide for multiple points of contact during actuation of the dispenser. For example, an actuator may be configured to include any desired number of contact surfaces to provide multiple points of contact with a push bar, thus providing a corresponding number of different drive lengths throughout the range of motion of the push bar. In addition or in the alternative, a push bar may be configured to include any desired number of contact points to provide multiple points of contact with an actuator throughout its range of motion. As another example, both the actuator and the push bar may be configured to provide multiple points of contact corresponding to a different number of drive lengths through the range of motion of the push bar. It shall be understood, therefore, that the disclosure is not limited to the specific examples shown and described herein, that many other variations of actuator and/or push bar configurations may be used, and that the disclosure is not limited in this respect. 
     Various examples have been described. These and other examples are within the scope of the following claims.