Patent Publication Number: US-2023145765-A1

Title: Locking cap for a drinking vessel

Description:
BACKGROUND 
     Devices for pouring contents contained therein typically include a container for containing contents, and a cap for closing the container. Known caps are designed to selectively engage and form a seal with the container for retaining the contents in the container; however, a continued design challenge of such caps is found in providing a cap with a reliable locking and sealing mechanism for a container in a compact space often associated with handheld containers. 
     SUMMARY 
     According to one aspect, a cap includes a housing, a flexible membrane made from a resilient material and disposed over at least a portion of the housing, a first slider at least partially disposed in the housing and movable between a first position and a second position with respect to the housing, and a second slider at least partially disposed in the housing and cooperating with the first slider. When the first slider is in the first position the second slider is in a locked position in which a distal end of the second slider presses against and extends the flexible membrane outwardly from the housing. When the first slider is in the second position the second slider is in an unlocked position in which the distal end of the second slider does not extend the flexible membrane outwardly from the housing as much as compared to the locked position. 
     According to another aspect, a method of assembling a cap includes disposing a flexible membrane over at least a portion of a housing, with an annular fin extending from the flexible membrane and configured to deform outwardly from the housing as pressure is applied to the annular fin from beneath the annular fin, providing a first slider at least partially disposed in a housing and moveable between a first position and a second position, and providing a second slider at least partially disposed in the housing in cooperation with the first slider and the flexible membrane such that when the first slider is in the first position the second slider is in a locked position in which a distal end of the second slider presses against and extends the flexible membrane outwardly from the housing, and when the first slider is in the second position the second slider is in an unlocked position in which the distal end of the second slider does not extend the flexible membrane outwardly from the housing as much as compared to the locked position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a front view of a cap connected with a vessel. 
         FIG.  2    is a side cross-sectional view of the cap connected with the vessel. 
         FIG.  3    is an enlarged cross-sectional view of the cap connected with the vessel shown in  FIG.  2    and locked with the vessel. 
         FIG.  4    is a cross-sectional front view of the cap on and unlocked from the vessel. 
         FIG.  5    is a partial cross-sectional front view of the cap removed from the vessel. 
         FIG.  6    is another partial cross-sectional side view of the cap connected with the vessel taken 90 degrees from the view shown in  FIG.  3   . 
         FIG.  7    is another partial cross-sectional side view of the cap on and unlocked from the vessel taken 90 degrees from the view shown in  FIG.  4   . 
         FIG.  8    is a perspective view of a button, a first slider, and a housing of the cap, with the slider in a first position with respect to the housing. 
         FIG.  9    is a perspective view of the button, the first slider, and the housing of the cap shown in  FIG.  8   , with the first slider driven by the button to a second position. 
         FIG.  10    is a perspective view of the button, the first slider, and the housing of the cap shown in  FIG.  9   , with the first slider rotated in a circumferential direction of the housing by the button. 
         FIG.  11    is a perspective view of the button, the first slider, and the housing of the cap shown in  FIG.  10   , with the button retracted from the first slider. 
         FIG.  12    is a perspective view of the button, the first slider, and the housing of the cap shown in  FIG.  11   , with the first slider rotated in the circumferential direction of the housing. 
         FIG.  13    is a perspective view of the button, the first slider, and the housing of the cap shown in  FIG.  12   , with the button pressed toward the first slider. 
         FIG.  14    is a perspective view of the button, the first slider, and the housing of the cap shown in  FIG.  13   , with the first slider rotated in the circumferential direction of the housing by the button. 
         FIG.  15    is a perspective view of the button, the first slider, and the housing of the cap shown in  FIG.  14   , with the button retracted from the first slider. 
         FIG.  16    is a perspective view of the button, the first slider, and the housing of the cap shown in  FIG.  15   , with the first slider in the first position with respect to the housing. 
         FIG.  17    is a partial cross-sectional front view of a cap according to another aspect connected and locked with the vessel. 
         FIG.  18    is a partial cross-sectional front view of a cap according to another aspect connected and locked with the vessel. 
         FIG.  19    is a partial cross-sectional front view of a cap according to another aspect unlocked and removed from the vessel. 
     
    
    
     DETAILED DESCRIPTION 
     It should, of course, be understood that the description and drawings herein are merely illustrative and that various modifications and changes can be made in the structures disclosed without departing from the present disclosure. Referring now to the drawings, wherein like numerals refer to like parts throughout the several views,  FIG.  1    depicts a cap  100  connected with a vessel  102 . As depicted in  FIG.  2   , the vessel  102  is formed from a vessel wall  104  that defines an interior  106  and an exterior of the vessel  102 , and defines an opening  110  from the interior  106  to the exterior of the vessel  102 . When the cap  100  is connected with the vessel  102 , a portion of the cap  100  is inserted in the opening  110  of the vessel  102 . With reference to  FIG.  3   , the cap  100  includes an upper cap  112 . The upper cap  112  has a shoulder  114  that obstructs the cap  100  from further insertion into the vessel  102 . With reference back to  FIG.  1    and to  FIG.  4   , lugs  120  connect with the upper cap  112  and the housing  124  via a respective post  122  that extends through the upper cap  112  to connect with a housing  124 . 
     With continued reference to  FIGS.  3  and  4   , a flexible membrane  130  made from a resilient material is disposed over at least a portion of the housing  124 . The resilient material from which the flexible membrane  130  can be made can include rubber-like materials such as silicone, and the upper cap  112  and the housing  124  are more rigid than the flexible membrane  130 . The housing  124  includes a wall portion  132  and a bottom portion  134 . The wall portion  132  defines a bore  136  extending in a longitudinal (axial) direction of the housing  124  from a top  138  of the housing  124  toward the bottom portion  134  to define an interior  140  of the housing  124 . The wall portion  132  further defines a first aperture  144  from the interior  140  to an exterior side  146  of the housing  124 , extended in a radial direction of the housing  124  orthogonal to the longitudinal direction of the housing  124 . The first aperture  144  is defined in the wall portion  132  where the wall portion  132  is configured for being inserted in the opening  110  of the vessel  102 . As described below, further apertures that have similar features and function in a similar manner can be defined in the wall portion  132 . For example, a group of three apertures including the first aperture  144  may be defined in the wall portion  132  and angularly spaced approximately 120° from each other in a circumferential direction of the housing  124  about the longitudinal direction. 
     In the illustrated embodiment, the wall portion  132  is cylindrical, with a central axis oriented in the longitudinal direction of the housing  124 . The wall portion  132  and the bottom portion  134  supports the flexible membrane  130 . While the depicted housing  124  is formed from the wall portion  132  and the bottom portion  134 , the housing  124  could alternatively be a cage or other rigid structure. 
       FIG.  2    depicts a front view of the cap  100  connected with the vessel  102 , with the cap  100  and the vessel  102  oriented in an upright position defined herein as the orientation resulting from standing the vessel  102  on a horizontal plane such that the longitudinal direction of the housing  124  is oriented normal to the horizontal plane. As shown in  FIG.  3   , an annular fin  150  extends downwardly from the flexible membrane  130  when the cap  100  is oriented in the upright position. In the illustrated embodiment, the annular fin  150  forms a continuous exterior surface of the cap  100  with the flexible membrane  130  along the housing  124  in the longitudinal direction of the housing  124 . 
     In the illustrated embodiment, the annular fin  150  is integrally formed with the flexible membrane  130  and made from the same material as the flexible membrane  130 , which results in the annular fin  150  being made from a resilient material. The annular fin  150  is configured to deform outwardly in the radial direction of the housing  124  as pressure in the vessel  102  is applied to the annular fin  150  from beneath the annular fin  150 , conforming to the interior  106  the vessel  102  below the opening  110 , and sealing the annular fin  150  against the vessel  102 . 
     With reference again to  FIGS.  3  and  4   , the vessel wall  104  defines a recess  152  at the opening  110  of the vessel  102  and includes a ramp  154  formed from the vessel wall  104  at a position below the recess  152  when the vessel  102  is oriented in the upright position. With the cap  100  inserted in the vessel  102 , the annular fin  150  presses against the ramp  154  as pressure is applied to the annular fin  150  from within the vessel  102  beneath the annular fin  150 , sealing the cap  100  with the vessel  102 . 
     With continued reference to  FIG.  3   , a first slider  160  is at least partially disposed in the housing  124 , and a first biasing member or spring  162  contacts the first slider  160  and the bottom portion  134  of the housing  124 . The first slider  160  is made from a rigid material, e.g. a rigid plastic.  FIG.  3    depicts the first slider  160  in a first position with respect to the housing  124 . The first slider  160  is movable along the longitudinal direction of the housing  124  between the first position and a second position. In the second position, the first slider  160  is located closer to the bottom portion  134  of the housing  124  as compared to when the first slider  160  is in the first position. The first spring  162  is a compression spring configured to bias the first slider  160  toward the first position and away from the second position in the longitudinal direction of the housing  124 , closer to the top  138  as compared to when the first slider  160  is in the second position. 
     The first slider  160  includes a first (upper) end portion  164  separated from a second (lower) end portion  166  by a recess  170 . The first end portion  164  and the second end portion  166  are complementary with an interior surface  172  of the housing  124  for sliding along the interior surface  172  between the first position and the second position. The first slider  160  includes a lower sloped face  174 , which forms part of the recess  170 , inclined inwardly in the radial direction of the housing  124 , along the longitudinal direction of the housing  124 . The lower sloped face  174  is located between the first end portion  164  and the second end portion  166  in the longitudinal direction of the housing  124 . 
     A second slider  180  is at least partially disposed in the housing  124 . The second slider  180  is made from a rigid material, e.g. a rigid plastic. The second slider  180  is positioned in the first aperture  144  between the first slider  160  and the flexible membrane  130  in the radial direction of the housing  124 . The second slider  180  includes a proximal end  182  configured for engaging the first slider  160  in the interior  140  of the housing  124 , and a distal end  184  configured for engaging the flexible membrane  130  at the exterior side  146  of the housing  124 . 
     The second slider  180  cooperates with the first slider  160  and the flexible membrane  130  such that when the first slider  160  is in the first position the second slider  180  is in a locked position in which the distal end  184  of the second slider  180  presses against and extends the flexible membrane  130  outwardly from the housing  124  in the radial direction of the housing  124 . The second slider  180  also cooperates with the first slider  160  such that when the first slider  160  is in the second position the second slider  180  is in an unlocked position in which the distal end  184  of the second slider  180  does not extend the flexible membrane  130  outwardly from the housing  124  as much as compared to the locked position. 
     The flexible membrane  130  is configured to conform to an exterior shape of the housing  124  and the distal end  184  of the second slider  180  when the second slider  180  is in either the locked position or the unlocked position. In this manner, the flexible membrane  130  is configured to deform around the distal end  184  of the second slider  180  in the radial direction of the housing  124  when the second slider  180  is in the locked position. In the illustrated embodiment, the flexible membrane  130  is also configured to conform with the exterior side  146  of the housing  124 , extending in the longitudinal direction of the housing  124 , straight along part of the wall portion  132  inserted in the vessel  102 , over the first aperture  144 , when the second slider  180  is in the unlocked position. 
     The lower sloped face  174  of the first slider  160  is inclined outward in the radial direction of the housing  124 , along the longitudinal direction of the housing  124 , from the first end portion  164  to the second end portion  166 . The lower sloped face  174  is configured to directly engage the second slider  180  when the first slider  160  moves between the first position and the second position. With this, the lower sloped face  174  of the first slider  160  directly contacts and drives the second slider  180  from the unlocked position toward the locked position when the first slider  160  moves from the second position toward the first position. When the first slider  160  moves from the first position toward the second position, the second slider  180  rides along the lower sloped face  174  into the recess  170 . 
     With continued reference to  FIG.  3   , the second slider  180  extends through the first aperture  144  and is configured to slide along the first aperture  144  in the radial direction of the housing  124  between the locked position and the unlocked position. In the locked position, the distal end  184  of the second slider  180  projects outward from the exterior side  146  of the housing  124 , causing the flexible membrane  130  to deform around the distal end  184  of the second slider  180  and generate a spring force against the distal end  184  of the second slider  180  toward the unlocked position. The spring force generated by the flexible membrane  130  when the second slider  180  is in the locked position is sufficient to bias the second slider  180  toward the unlocked position. In this manner, the flexible membrane  130  drives the second slider  180  toward the unlocked position when the first slider  160  is in the second position. 
     The distal end  184  of the second slider  180  is rounded toward the first slider  160 , along the circumferential direction of the housing  124 . As such, when the second slider  180  is in the locked position, the flexible membrane  130  deforms outward from the exterior side  146  of the housing  124  with a rounded shape. The rounded shape of the flexible membrane  130  over the second slider  180  is complementary with the recess  152  for locking the cap  100  with the vessel  102 . With the flexible membrane  130  having a rounded shape complementary with the recess  152 , the cap  100  is configured to evenly dissipate forces exerted on the cap  100  relative to the vessel  102  along the rounded shape of the flexible membrane  130 , retaining the cap  100  in the opening  110  of the vessel  102  when the cap  100  is connected with and locked with the vessel  102 . 
       FIGS.  3 - 5    depict successive stages of the cap  100  being removed from the vessel  102 .  FIG.  3    depicts the cap  100  locked in the opening  110  of the vessel  102 ,  FIG.  4    depicts the cap  100  unlocked in the opening  110  of the vessel  102 , and  FIG.  5    depicts the cap  100  removed from the vessel  102 . 
     As shown in  FIG.  4   , the distal end  184  of the second slider  180  in the unlocked position is retracted toward the interior  140  of the housing  124  as compared to when the second slider  180  is in the locked position. In the illustrated embodiment, the distal end  184  of the second slider  180  is flush with or retracted inward from the exterior side  146  of the housing  124  in the radial direction of the housing  124  such that the flexible membrane  130  extends over the first aperture  144  unobstructed by the second slider  180 . The exterior of the cap  100  defined by the flexible membrane  130  extends straight along the housing  124  in the longitudinal direction of the housing  124 , over the second slider  180  in the radial direction of the housing  124 , spaced from the vessel wall  104 . As such, the second slider  180  and the flexible membrane  130  at the wall portion  132  do not obstruct the cap  100  from moving relative to the vessel  102  in the longitudinal direction of the housing  124 . In this manner, the cap  100  is configured for being removed from the vessel  102  in the longitudinal direction of the housing  124 . 
     As shown in  FIG.  5   , the cap  100  is removed from the vessel  102  by being displaced from the vessel  102  in the longitudinal direction of the housing  124 . The first slider  160  is held in the second position with the second slider  180  disposed in the unlocked position such that the portion of the cap  100  inserted in the vessel  102  in  FIG.  4    can move along the vessel wall  104  in the longitudinal direction of the housing  124 , removing the cap  100  from the vessel  102 . 
     With reference to  FIG.  3   , the cap  100  includes a flexible cover  190  connected to the upper cap  112  and covering the first slider  160 . The flexible cover  190 , the upper cap  112 , and the flexible membrane  130  cooperate to prevent ingress of liquid into the interior  140  of the housing  124 . More specifically, the upper cap  112 , the flexible membrane  130  and the flexible cover  190  are supported by and encase the exterior side  146  of the housing  124 , sealing the exterior of the cap  100  from the housing  124 . 
     The cap  100  also includes an actuator  192  cooperating with the first slider  160  and interposed between the flexible cover  190  and the first slider  160  in the longitudinal direction of the housing  124 . The actuator  192  will be described hereinafter as a button, where the button  192  is at least partially disposed in the housing  124 , extends into the bore  136  in the housing  124  when the first slider  160  is in the first position, and is configured, when pressed downward per the orientation shown, to drive the first slider  160  away from the first position and toward the second position. The button  192  is configured to selectively interlock with the first slider  160  when the button  192  drives the first slider  160  toward the second position, and rotate the first slider  160  with respect to the housing  124 . While the described actuator  192  is a button, the actuator  192  may alternatively be a switch or other type of control configured to actuate the first slider  160  between the first position and the second position for selectively locking the cap  100  with the vessel  102  without departing from the scope of the present application. 
     A second biasing member or spring  194  can be interposed between the first slider  160  and the button  192  in the longitudinal direction of the housing  124 . The second spring  194  is a compression spring configured to bias the button  192  away from the first slider  160 , toward the flexible cover  190 . The second spring  194  is disposed in a cavity  196  defined by the first slider  160  and the button  192  and configured for retaining the second spring  194  between the first slider  160  and the button  192  when the first slider  160  is in the first position and when the first slider  160  is in the second position, whether the button  192  is engaged with the first slider  160  or the button  192  is biased away from the first slider  160 . 
     The flexible cover  190  covers the button  192  and the first slider  160  in the interior  140  of the housing  124 . When the first slider  160  is in the first position, the button  192  abuts the flexible cover  190  and is configured for being pressed through the flexible cover  190  in the longitudinal direction of the housing  124 , driving the first slider  160  toward the second position. As shown in  FIG.  4   , the flexible cover  190  deforms through the bore  136 , into the interior  140  of the housing  124  when the button  192  is pressed through the flexible cover  190 , driving the first slider  160  to the second position. The flexible cover  190  is configured to deform elastically when pressed into the interior  140  of the housing  124 , and generate a spring force that returns the flexible cover  190  to an undeformed state when the flexible cover  190  is no longer being pressed. In an embodiment where the button  192  is fixed to the flexible cover  190 , the flexible cover may “spring back” the button  192  with the spring force after being pressed into the interior  140  of the housing  124  in addition or alternative to the first spring  162  and the second spring  194 . 
     With reference to  FIG.  3   , the wall portion  132  defines a second aperture  198  from the interior  140  to the exterior side  146  of the housing  124 , extended in the radial direction of the housing  124  and angularly spaced from the first aperture  144  by approximately 120°. A third slider  200  is at least partially disposed in the housing  124  in the second aperture  198 , between the first slider  160  and the flexible membrane  130  in the radial direction of the housing  124 . The second aperture  198  and the third slider  200  have similar features and function in a similar manner as the first aperture  144  and the second slider  180  with respect to the first slider  160  and the flexible membrane  130 . In view of this further description is omitted for the sake of brevity. 
     As shown in  FIG.  6   , the wall portion  132  defines a third aperture  204  from the interior  140  to the exterior side  146  of the housing  124 , extended in the radial direction of the housing  124  and angularly offset from the first aperture  144  and the second aperture  198  by approximately 120°. A fourth slider  210  is at least partially disposed in the housing  124  at the third aperture  204 , between the first slider  160  and the flexible membrane  130  in the radial direction of the housing  124 . The third aperture  204  and the fourth slider  210  have similar features and function in a similar manner as the first aperture  144  and the second slider  180  with respect to the first slider  160  and the flexible membrane  130 . In view of this further description is omitted for the sake of brevity. 
     As shown between  FIGS.  3  and  6   , the first aperture  144 , the second aperture  198 , and the third aperture  204  are arranged evenly spaced from each other in the circumferential direction of the housing  124  at approximately 120° intervals. As such, when the cap  100  is connected with the vessel  102  and the first slider  160  is in the first position, the second slider  180 , the third slider  200 , and the fourth slider  210  are respectively disposed in the locked position, where the distal end  184  of the second slider  180 , the distal end  202  of the third slider  200 , and the distal end  212  of the fourth slider  210  are positioned with approximately even spacing along the exterior side  146  of the housing  124  in the circumferential direction of the housing  124 . The distal end  184  of the second slider  180 , the distal end  202  of the third slider  200 , and the distal end  212  of the fourth slider  210  are pressed and extended toward the recess  152  with the flexible membrane  130 , obstructing the cap  100  from moving in the longitudinal direction of the housing  124  relative to the vessel  102 . 
     In this manner, the recess  152  in the vessel wall  104  is configured to receive the flexible membrane  130 , the distal end  184  of the second slider  180 , the distal end  202  of the third slider  200 , and the distal end  212  of the fourth slider  210 , locking the cap  100  with the vessel  102  when the second slider  180 , the third slider  200 , and the fourth slider  210  are respectively disposed in the locked position. With the distal end  184  of the second slider  180 , the distal end  202  of the third slider  200 , and the distal end  212  of the fourth slider  210  positioned with approximately even spacing in the circumferential direction of the housing  124 , forces exerted on the cap  100  relative to the vessel  102  are evenly distributed in the recess  152  of the vessel  102  between the second slider  180 , the third slider  200 , and the fourth slider  210 , retaining the cap  100  in the vessel  102  when the cap  100  connected and locked with the vessel  102 . 
     The second slider  180 , the third slider  200 , and the fourth slider  210  form a plurality of sliders  180 ,  200 ,  210  least partially disposed in the housing  124 , cooperating with the first slider  160  and the flexible membrane  130 , and are arranged approximately evenly spaced from each other in the circumferential direction of the housing  124 . Notably, the plurality of sliders  180 ,  200 ,  210  may alternatively include more or fewer sliders having similar features and functioning in a similar manner as the second slider  180 , the third slider  200 , and the fourth slider  210  without departing from the scope of the present application. 
       FIG.  6    depicts the first slider  160  disposed in the first position, where the first slider  160  is biased in a position against a first stop  214  provided in the housing  124  such that the first stop  214  retains the first slider  160  in the first position.  FIG.  7    depicts the first slider  160  disposed in the second position, where the first slider  160  is biased in a position against a second stop  216  attached to the housing  124  such that the second stop  216  retains the first slider  160  in the second position. The button  192  is configured to drive the first slider  160  toward the second position and rotate the first slider  160  in the circumferential direction of the housing  124  for engaging one of the first stop  214  and the second stop  216 . 
       FIGS.  8 - 16    depict the first slider  160  and the button  192  in the housing  124  through successive stages where the button  192  drives the first slider  160  toward the second position, rotating the first slider  160  in the circumferential direction of the housing  124  such that the first stop  214  retains the first slider  160  in the first position, or the second stop  216  retains the first slider  160  in the second position. 
     The button  192  includes ramped surfaces  218  inclined in the circumferential direction of the housing  124 , and the first slider  160  includes ramped surfaces  220  inclined in the circumferential direction of the housing  124 , facing in a direction opposite the ramped surfaces  218  of the button  192 . The ramped surfaces  220  of the first slider  160  are complementary with the ramped surfaces  218  of the button  192  such that when the button  192  is pressed to drive the first slider  160  toward the second position, the ramped surfaces  218  of the button  192  press the ramped surfaces  220  of the first slider  160  in the circumferential direction of the housing  124 . The ramped surfaces  220  of the first slider  160  slide along the ramped surfaces  218  of the button  192 , rotating the first slider  160  in the circumferential direction of the housing  124  relative to the button  192 . 
     The housing  124  includes rails  222  extended along the longitudinal direction of the housing  124 , in the interior  140  of the housing  124 . The rails  222  are configured to retain a radial position of the button  192  with respect to the housing  124  when the button  192  rotates the first slider  160 . The button  192  is arranged at the top  138  of the housing  124  and cooperates with the first slider  160  such that when the first slider  160  is in the first position a distal face  224  of the button  192  is extended outward from the exterior side  146  of the housing  124  in the longitudinal direction of the housing  124 , and when the button  192  drives the first slider  160  toward the second position the distal face  224  of the button  192  is retracted inward of the exterior side  146  of the housing  124  in the longitudinal direction of the housing  124 . In the depicted embodiment, the first stop  214  ( FIG.  6   ) and the second stop  216  ( FIG.  7   ) are respectively formed from bottom portions of the rails  222 . 
       FIGS.  8 - 11    depict the button  192  driving the first slider  160  toward the second position where the first slider  160  is retained in the second position by the second stop  216 . Specifically,  FIG.  8    depicts the first slider  160  biased in the first position and engaged with the button  192 .  FIG.  9    depicts the first slider  160  driven in the second position by the button  192 .  FIG.  10    depicts the first slider  160  in the second position and rotated relative to the housing  124  by the button  192  in the circumferential direction of the housing  124 .  FIG.  11    depicts the first slider  160  in the second position with the button  192  retracted from the first slider  160 , where the first slider  160  is retained in the second position by the second stop  216  ( FIG.  7   ). In this manner, the button  192  is configured to selectively engage and interlock with the first slider  160 , drive the first slider  160  toward the second position, and rotate the first slider  160  such that the first slider  160  engages the second stop  216 , locking the first slider  160  in the second position. 
       FIGS.  12 - 16    depict the button  192  driving the first slider  160  toward the second position where the first slider  160  is retained in the first position by the first stop  214 . Specifically,  FIG.  12    depicts the first slider  160  driven in the second position and rotated relative to the housing  124  by the button  192  in the circumferential direction of the housing  124 .  FIG.  13    depicts the first slider  160  driven in the second position by the button  192 .  FIG.  14    depicts the first slider  160  driven in the second position and rotated in the circumferential direction of the housing  124  by the button  192 .  FIG.  15    depicts the first slider  160  in the second position with the button  192  retracted from the first slider  160 .  FIG.  16    depicts the first slider  160  biased in the first position, where the first slider  160  is retained in the first position by the first stop  214  ( FIG.  6   ). In addition or alternative to the first stop  214 , the button  192  may be configured to retain the first slider  160  in the first position, where the first slider  160  is biased in the first position against the button  192 , without departing from the scope of the present application. In this manner, the button  192  is configured to selectively engage and interlock with the first slider  160 , drive the first slider  160  toward the second position, and rotate the first slider  160  such that the first slider  160  engages the first stop  214 , locking the first slider  160  in the first position. 
     With reference to  FIG.  3   , a method of assembling the cap  100  includes disposing the flexible membrane  130  over at least a portion of a housing  124 , with the annular fin  150  extending downwardly from the flexible membrane  130  and configured to deform outwardly as pressure is applied to the annular fin  150  from beneath the annular fin  150 . The method of assembling the cap  100  also includes providing the first slider  160  at least partially disposed in the housing  124  and moveable between the first position and the second position. The method of assembling the cap  100  also includes providing the second slider  180  at least partially disposed in the housing  124  in cooperation with the first slider  160  and the flexible membrane  130  such that when the first slider  160  is in the first position the second slider  180  is in the locked position, where the distal end  184  of the second slider  180  presses against and extends the flexible membrane  130  outwardly from the housing  124 , and when the first slider  160  is in the second position the second slider  180  is in the unlocked position where the distal end  184  of the second slider  180  does not extend the flexible membrane  130  outwardly from the housing  124  as much as compared to the locked position. 
     In an embodiment, the method of assembling the cap  100  also includes providing the button  192  at least partially disposed in the housing  124 , cooperating with the first slider  160 . The method of assembling the cap  100  also includes covering the first slider  160  and the button  192  in the housing  124  with the flexible cover  190  such that the button  192  is interposed between the flexible cover  190  and the first slider  160 . The method of assembling the cap  100  also includes fixing the flexible cover  190  with the flexible membrane  130  such that the flexible cover  190 , the upper cap  112 , and the flexible membrane  130  cooperate to prevent ingress of liquid into the interior  140  of the housing  124 . 
     In an embodiment, the method of assembling the cap  100  also includes providing the plurality of sliders  180 ,  200 ,  210 , including the second slider  180 , at least partially disposed in the housing  124  and cooperating with the first slider  160  and the flexible membrane  130  such that when the first slider  160  is in the first position the plurality of sliders  180 ,  200 ,  210  are in the locked position in which the distal end  184 ,  202 ,  212  of each slider  180 ,  200 ,  210  in the plurality of sliders  180 ,  200 ,  210  presses against and extends the flexible membrane  130  outwardly from the housing  124 , and when the first slider  160  is in the second position the plurality of sliders  180 ,  200 ,  210  are in the unlocked position in which the distal end  184 ,  202 ,  212  of each slider  180 ,  200 ,  210  in the plurality of sliders  180 ,  200 ,  210  does not extend the flexible membrane  130  outwardly from the housing  124  as much as compared to the locked position, and the plurality of sliders  180 ,  200 ,  210  are arranged evenly spaced from each other along the circumferential direction of the housing  124 . 
       FIG.  17    illustrates a cap  300  as an alternate embodiment of the cap  100  of  FIGS.  1 - 16   . With respect to the cap  300  of  FIG.  17   , like elements with the cap  100  of  FIGS.  1 - 16    are denoted with the same reference numerals but followed by a primed suffix (′). 
       FIG.  17    depicts the cap  300  locked in the opening  110  of the vessel  102 . As shown in  FIG.  17   , the cap  300  includes a first slider  302  at least partially disposed in the housing  124 ′, and the first spring  162 ′ contacts the first slider  302  and the bottom portion  134 ′ of the housing  124 ′. The first slider  302  is movable along the longitudinal direction of the housing  124 ′ between a first position and a second position relative to the housing  124 ′, and is biased toward the first position by the first spring  162 ′. The first slider  302  is configured to drive the second slider  180 ′ between the locked position and the unlocked position through the lower sloped face  174 ′ as the first slider  302  is driven between the first position and the second position. 
     An actuator or button  304  is integrally formed with the first slider  302  and interposed between the flexible cover  190 ′ and the first slider  302  in the longitudinal direction of the housing  124 ′. The button  304  is at least partially disposed in the housing  124 ′, extends outward from the housing  124 ′ when the first slider  302  is in the first position, and is configured to drive the first slider  302  away from the first position and toward the second position when pressed through the flexible cover  190 ′. 
     With the button  304  integrally formed with the first slider  302 , the button  304  is configured to move with the first slider  302  between the first position and the second position. The cap  300  includes a stop  306  fixed with the housing  124  and extended into a notch  308  defined in the button  304  to obstruct the first slide  302  from moving beyond the first position from the second position. In this manner the stop  306  is configured to retain the first slider  302  in the first position against the bias from the first spring  162 ′. The depicted embodiment lacks a stop configured to retain the first slider  302  in the second position such that when the button  304  is not pressed to drive the first slider  302  toward the second position, the first slider  302  is retained in the first position, with the second slider  180 ′ in the locked position. 
       FIGS.  18  and  19    illustrate a cap  400  as an alternate embodiment of the cap  100  of  FIGS.  1 - 16   , where  FIG.  18    depicts the cap  400  locked in the opening  110  of the vessel  102 , and  FIG.  19    depicts the cap  400  unlocked and removed from the opening  110  of the vessel  102 . With respect to the cap  400  of  FIGS.  18  and  19   , like elements with the cap  100  of  FIGS.  1 - 16    are denoted with the same reference numerals but followed by a primed suffix (′). 
     As shown in  FIG.  18   , the cap  400  includes a first slider  402  disposed on the housing  124 ′, and the first biasing member or spring  162 ′ contacts the first slider  402  and the bottom portion  134 ′ of the housing  124 ′. The first slider  402  is movable along the longitudinal direction of the housing  124 ′ between a first position and a second position relative to the housing  124 ′, and is biased toward the first position by the first spring  162 ′, against a rigid cover  404 . The rigid cover  404  is spaced from the housing  124 ′ in the longitudinal direction of the housing  124 ′, and extends from the upper cap  112 ′ transversely across the bore  136 ′, in the radial direction of the housing  124 ′. 
     The cap  400  includes a flexible cover  410  connected to the upper cap  112 ′ and positioned over the rigid cover  404  with respect to an exterior of the cap  400 . The flexible cover  410 , the upper cap  112 ′, and the flexible membrane  130 ′ cooperate to prevent ingress of liquid into the interior  140 ′ of the housing  124 ′. More specifically, the upper cap  112 ′, the flexible membrane  130 ′, and the flexible cover  410  are supported by and encase the exterior side  146 ′ of the housing  124 ′, sealing the exterior of the cap  400  from the housing  124 ′. 
     The cap  400  also includes a first actuator  412  and a second actuator  414 , described hereinafter as a first button and a second button, where the first button  412  and the second button  414  respectively cooperate with the first slider  402  to drive the first slider  402  away from the first position and toward the second position. The rigid cover  404  is disposed over the first button  412  and the second button  414 , and the flexible cover  410  is disposed over the rigid cover  404 , the first button  412 , and the second button  414  in the longitudinal direction of the housing  124 ′. The flexible cover  410  extends from the housing  124 ′ to the rigid cover  404  in the longitudinal direction of the housing  124 ′ such that the first button  412  and the second button  414  can be pressed through the flexible cover  410 , inward in the radial direction of the housing  124 ′, and slide along the housing  124 ′ and the rigid cover  404 . 
     The first button  412  and the second button  414  are each disposed on the housing  124 ′, and extended across the bore  136 ′ in the radial direction of the housing  124 ′ to be interposed between the rigid cover  404  and the first slider  402  in the longitudinal direction of the housing  124 ′, and interposed between the first slider  402  and the flexible cover  410  in the radial direction of the housing  124 ′. The first button  412  and the second button  414  are disposed on opposite sides of the housing  124 ′ with respect to the radial direction of the housing  124 ′, and directly contact the first slider  402  at opposite sides of the first slider  402  with respect to the radial direction of the housing  124 ′. As shown in  FIG.  19   , the first button  412  and the second button  414  are each configured to drive the first slider  402  away from the first position and toward the second position when pressed inward in the radial direction of the housing  124 ′. 
     With reference to  FIG.  19   , the first button  412  includes a first button body portion  420  extended through a first channel  422  defined between the housing  124 ′ and the rigid cover  404  in the longitudinal direction of the housing  124 ′. The first channel  422  extends in the radial direction of the housing  124 ′ from the interior  140 ′ to the exterior side  146 ′ of the housing  124 ′. The first button body portion  420  is configured for being pressed inward in the radial direction of the housing  124 ′ through the flexible cover  410 , into the first channel  422  such that the first button body portion  420  slides against the rigid cover  404  and the housing  124 ′ along the first channel  422  in the radial direction of the housing  124 ′. 
     The first button  412  includes a first wedge portion  424  extended from the first button body portion  420  toward the first slider  402  in the radial direction of the housing  124 ′. The first wedge portion  424  has a first button inclined face  430  that is inclined upward per the orientation shown, along the radial direction housing  124 ′ toward the first slider  402 . The first button inclined face  430  directly contacts, extends along, and is configured to slide against a corresponding first slider inclined face  432  formed on the first slider  402 . The first slider inclined face  432  is complementary to the first button inclined face  430  such that the first wedge portion  424  drives the first slider  402  away from the first position and toward the second position through the first button inclined face  430  when the first button body portion  420  is pressed inward in the radial direction of the housing  124 ′. As shown in  FIG.  18   , when the first button body portion  420  is not pressed inward in the radial direction of the housing  124 ′, the spring  162 ′ drives the first slider  402  toward the first position, against the rigid cover  404 , and the first slider  402  drives the first button  412  through the first slider inclined face  432 , outward in the radial direction of the housing  124 ′ and against the flexible cover  410 . 
     The second button  414  includes similar features, and functions in a similar manner as the first button  412  with respect to the housing  124 ′, the first slider  402 , the rigid cover  404 , and the flexible cover  410 . With reference to  FIG.  19   , the second button  414  includes a second button body portion  434  extended through a second channel  440  defined between the housing  124 ′ and the rigid cover  404  in the longitudinal direction of the housing  124 ′. The second channel  440  extends in the radial direction of the housing  124 ′ from the interior  140 ′ to the exterior side  146 ′ of the housing  124 ′. The second button body portion  434  is configured for being pressed inward in the radial direction of the housing  124 ′ through the flexible cover  410 , into the second channel  440  such that the second button body portion  434  slides against the rigid cover  404 , along the second channel  440  in the radial direction of the housing  124 ′. 
     The second button  414  includes a second wedge portion  442  extended from the second button body portion  434  toward the first slider  402  in the radial direction of the housing  124 ′. The second wedge portion  442  has a second button inclined face  444  that is inclined upward per the orientation shown, along the radial direction housing  124 ′ toward the first slider  402 . The second button inclined face  444  directly contacts, extends along, and is configured to slide against a corresponding second slider inclined face  450  formed on the first slider  402 . The second slider inclined face  450  is complementary to the second button inclined face  444  such that the second wedge portion  442  drives the first slider  402  away from the first position and toward the second position through the second button inclined face  444  when the second button body portion  434  is pressed inward in the radial direction of the housing  124 ′. As shown in  FIG.  18   , when the second button body portion  434  is not pressed inward in the radial direction of the housing  124 ′, the spring  162 ′ drives the first slider  402  toward the first position, and the first slider  402  drives the second button  414  through the second slider inclined face  450 , outward in the radial direction of the housing  124 ′ and against the flexible cover  410 . 
     The first slider  402  is configured to drive the second slider  180 ′ between the locked position and the unlocked position through the lower sloped face  174 ′ as the first slider  402  is driven between the first position and the second position. The depicted embodiment lacks a stop configured to retain the first slider  402  in the second position such that when the first button  412  and the second button  414  are not pressed to drive the first slider  402  toward the second position, the first slider  402  is retained in the first position, with the second slider  180 ′ in the locked position. 
     It will be appreciated that the above-disclosed embodiments and other features and functions, or alternatives or varieties thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.