Abstract:
A container for storing and dispensing viscous liquids which dispenses from the bottom of the container and which has a self-closing, non-drip dispensing spout. The dispensing spout may be provided on the bottom of an upright container having a cap at the other extremity or as a part of a removable cap for the container having a flat upper surface for storing the container in an inverted position. A self-operating closure allows one-handed operation of the container. The self-operating closure has a pivotable dispensing tube and valve with an open position and a closed position which is operated by the pivoting action of the dispensing tube. The pivotable dispensing tube and the valve are biased into a closed position to make the closure self-operating. A detent may be provided for holding the pivotable dispensing tube in an open position against the bias. The closure is operated by urging the pivotable dispensing tube past the detent, either manually or by setting the dispensing bottle down on a horizontal surface, whereupon the dispensing tube and therefore the valve are urged to a closed position. The fluid passage through the pivotable dispensing spout is configured so that, when the dispensing spout is in the closed position, any fluid within the passage will tend to flow back toward the closed valve instead of dripping from the end of the dispensing tube.

Description:
CROSS REFERENCE TO OTHER APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 09/241,593 filed Feb. 2, 1999, now U.S. Pat. No. 6,161,737 issued Dec. 19, 2000, which is a continuation-in-part of U.S. patent application No. 08/713,819 filed Sep. 13, 1996, now U.S. Pat. No. 5,865,352, issued Feb. 2, 1999, which claims priority of U.S. Provisional Application No. 60/003,812 issued Sep. 15, 1995. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to containers and dispensers. More particularly, the invention relates to a container for storing and dispensing viscous liquids which dispenses from the bottom of the container and which has a self-closing, non-drip dispensing spout. 
     BACKGROUND OF THE INVENTION 
     Viscous liquids, such as liquid soap, hand lotion, sun screen, shampoo, hair conditioner, or food condiments like mustard, catchup, mayonnaise, etc., pose particular difficulties in dispensing. The viscosity of these liquids makes it difficult to dispense them from standard, top-opening containers because the liquid tends stay in the bottom of the container even when the container is inverted. It often takes considerable patience on the part of the user to wait until the viscous liquid reaches the opening or the dispensing spout on the top of the container after the container is inverted. If the container is only partially full or if the liquid is particularly viscous, the weight of the liquid by itself is sometimes not enough to create sufficient shear force to overcome the viscosity and to initiate flow. The user must frequently resort to shaking or banging the container to coax the liquid out. It would be much more convenient for the user if the liquid were always close to the opening or dispensing tube of the container so that it is immediately ready to be dispensed. 
     One attempted solution to this problem that has been available for years is the use of pump-type dispensers on containers for viscous liquids. The dispenser pump typically has a scavenging tube which reaches down to the bottom of the container. 
     Once the pump is primed with the liquid, it generally stays primed so that the liquid can immediately be dispensed by pressing on the pump without waiting for the liquid to rise from the bottom of the container. This, however, is an incomplete solution to the problem. Pump-type dispensers are rarely effective at dispensing all of the liquid which is inside the container, especially when the liquid is viscous. Some liquid nearly always remains in the bottom of the container beyond the reach of the scavenging tube. This is wasteful and it is frequently frustrating to the user who struggles to get the last bit of product out of the container. Particularly with viscous liquids, the dispenser pumps are also prone to dripping between uses which causes some small mess on the counter or shelf or on the outside of the container. Another problem with this solution is that the long, thin tubes that lead to and from the pump mechanism have a tendency to clog when the liquid dries or thickens in the tubes between uses. The complexity of dispensing pumps also makes them prone to breakage or mechanical failure and also adds to the expense of the container. Pump dispensers of this type are convenient for stationary, countertop use, but they pose special problems when traveling because the pump mechanism can be inadvertently activated inside of the user&#39;s luggage or purse when something presses against the pump when closing the luggage or when things move around inside the luggage during travel or baggage handling. Adding a locking mechanism or overcap to the pump dispenser for storage or travel solves this problem, but it increases the complexity and cost of the container. 
     Another solution to the problems associated with dispensing viscous liquids which has gained recent popularity in the packaging industry is the use of self-standing tube containers. Typically, a self-standing tube container consists of a flexible plastic squeeze tube or bottle with a screw-on cap that is adapted to act as a base to stand the tube on its end. The cap may be a simple screw-on lid or it may have a flip-top or a dispensing tube or spout incorporated into the cap. The cap is made with a wide, flat end surface that provides a stable base for standing the tube or bottle up on its end. Because the closed end of a squeeze tube is pointed, the cap is generally the only surface of the container suitable for standing the tube on a shelf, insuring that the container will always be stored in the correct inverted position. Likewise, when the container is a flexible plastic bottle, the end of the bottle opposite the cap is sometimes made with a rounded end so that the cap is the only surface suitable to stand the bottle on a shelf. Because the container rests on the shelf in an inverted position with the cap down, the liquid inside always settles near the opening or dispensing tube of the container for immediate dispensing. However, this too is an incomplete solution to the problem. Simple screw-on caps are inconvenient in this application, because it often requires three hands to operate them. If a user has picked up a container of, say, hand lotion with one hand and taken the cap off with the other hand, the user must put the cap down in order to dispense the hand lotion onto the free hand. Now the user has the container in one hand and a dollop of hand lotion in the other. He or she does not have a free hand left to pick the cap up and put it back on the container. However, he or she cannot set the tube down to finish applying the hand lotion because the only standing surface on the container is on the cap which is currently lying by itself on the countertop. This frustrating situation usually results in odd contortions or careful juggling acts to apply the lotion or to finagle the cap back onto the container without a free hand. Flip-top caps or caps with built-in dispensing tubes simplify this problem because the cap remains attached to the container during dispensing, but it is still difficult to close the container without a free hand so that it can be set down while applying the dispensed lotion. It would be desirable therefore to provide a container which does not require a spare hand and can close itself after the user is through with dispensing. 
     SUMMARY OF THE INVENTION 
     In keeping with the foregoing discussion, an objective of the present invention is to provide a bottom-dispensing container where the liquid to be dispensed is always near the dispensing spout of the container when it is stored. This allows immediate dispensing of the liquid without having to wait for the liquid to reach the dispensing spout. In one aspect of the invention, the dispensing spout may be provided on the bottom of an upright container having a cap at the other extremity. In another aspect of the invention, the dispensing tube may be provided in a removable cap for the container having a flat upper surface for storing the container in an inverted position. 
     Another objective of the present invention is to provide the dispensing container with a self-operating closure which allows one-handed operation of the container so that another hand is not needed for operating the closure. In one aspect of the invention, the self-operating closure is provided with a pivotable dispensing tube having a fluid passage therethrough which communicates with the interior of the container, preferably near the bottom of the container. The pivotable dispensing tube has a valve with an open position and a closed position which is operated by the pivoting action of the dispensing tube. A biasing means urges the pivotable dispensing tube and the valve into a closed position to make the closure self-operating. 
     In another aspect of the invention, a detent may be provided for holding the pivotable dispensing tube in an open position against the urging of the biasing means. The closure is operated by urging the pivotable dispensing tube past the detent, either manually or by setting the dispensing bottle down on a horizontal surface, whereupon the biasing means operates to move the dispensing tube and therefore the valve to a closed position. In a preferred embodiment, the pivotable dispensing tube and the dispensing container are configured so that the act of setting the container down on a horizontal surface, such as a shelf or countertop, provides the force to urge the pivotable dispensing tube past the detent to initiate the self-closing action. In yet another aspect of the invention, the self-operating closure has incorporated therein a non-drip feature. The non-drip feature is provided by configuring the fluid passage within the pivotable dispensing spout so that, when the dispensing spout is in the closed position, any fluid within the passage will tend to flow back toward the closed valve instead of out the end of the dispensing tube. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1A and 1B show a first embodiment of the dispensing bottle of the present invention with the pivotable dispensing tube in the closed position and open position, respectively. 
     FIG. 1C is an exploded view of the dispensing bottle of FIGS. 1A and 1B. 
     FIG. 2 is an exploded view of the dispensing bottle of the present invention showing a first embodiment of the biasing means for urging the pivotable dispensing tube into the closed position. 
     FIG. 3A is a perspective view of the dispensing bottle of the present invention showing a second embodiment of the biasing means for urging the pivotable dispensing tube into the closed position. FIG. 3B is an enlarged view of the pivotable dispensing tube of the dispensing bottle of FIG.  3 A. 
     FIG. 3C is a partial cross section of the pivotable dispensing tube of FIG. 3B taken along the line  3 C— 3 C. 
     FIGS. 4A and 4B show a second embodiment of the dispensing bottle of the present invention with the pivotable dispensing tube in the closed position and open position, respectively. 
     FIGS. 5A and 5B show a third embodiment of the dispensing bottle of the present invention with the pivotable dispensing tube in the closed position and open position, respectively. 
     FIG. 6A shows a perspective view of a fourth embodiment of the dispensing bottle of the present invention with the dispensing tube incorporated into a disk-shaped rotating dispensing spout. 
     FIG. 6B is a cross section of the dispensing bottle of FIG. 6A taken along the line  6 B— 6 B. 
     FIG. 6C shows a variation of the fourth embodiment configured to be attached to a standard threaded-neck bottle. 
     FIGS. 7A and 7B show a fifth embodiment of the dispensing bottle of the present invention with the pivotable dispensing tube in the closed position and open position, respectively. 
     FIGS. 8A and 8B show a sixth embodiment of the dispensing bottle of the present invention with the pivotable dispensing tube in the closed position and open position, respectively. 
     FIG. 8C shows a variation of the sixth embodiment configured to be attached to a standard threaded-neck bottle. 
     FIGS. 9A,  9 B and  9 C illustrate the operation of the dispensing bottle of FIGS. 7A and 7B. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A first embodiment of the dispensing bottle  10  of the present invention is shown in FIGS. 1A,  1 B and  1 C. The dispensing bottle  10  has a liquid container  12  for holding a liquid, such as liquid soap, hand lotion, etc. Preferably, the liquid container  12  portion of the dispensing bottle  10  is molded of flexible plastic material, such as polyethylene or polypropylene, using known molding techniques, such as injection molding, blow molding or rotational molding. A pivotable dispensing tube  14  is pivotably attached to the liquid container  12 , preferably near the bottom of the liquid container  12 . A hollow pivot pin  16  extends from the side of the liquid container  12  and engages a transverse pivot hole  18  through the pivotable dispensing tube  14 . The hollow pivot pin  16  can be molded integrally with the liquid container  12  or it can be molded as a separate piece and assembled to the liquid container  12 , for example by ultrasonic welding or other known joining processes, as shown in FIG. 1C. A first fluid passage  20  extends through the hollow pivot pin  16  connecting the interior of the fluid container  12  with a discharge port  22  located in the side of the hollow pivot pin  16 . 
     A second fluid passage  24  extends through the pivotable dispensing tube  14  from the distal end  26  of the tube  14  to the transverse pivot hole  18 . When the pivotable dispensing tube  14  is in the open position, as shown in FIG. 1B, the second fluid passage  24  aligns with the discharge port  22  in the side of the hollow pivot pin  16 . When the pivotable dispensing tube  14  is in the closed position, as shown in FIG. 1A, the second fluid passage  24  moves out of alignment with the discharge port  22 , thereby acting like a valve to close off fluid flow between the first fluid passage  20  and the second fluid passage  24 . In a preferred embodiment, the second fluid passage  24  within the pivotable dispensing tube  14  is configured so that, when the pivotable dispensing tube  14  is in the closed position and the base  30  of the dispensing bottle  10  is horizontal, the distal end  26  of the second fluid passage  24  is higher than the proximal end  28 . That way, when the pivotable dispensing tube  14  is closed and the dispensing bottle  10  is placed on a level surface, such as a shelf or countertop, any liquid remaining in the second fluid passage  24  tends to flow back into the passage  24  rather than flowing out the open distal end  26 . This feature eliminates dripping from the dispensing bottle  10  between uses. 
     In a preferred embodiment of the dispensing bottle  10 , the pivotable dispensing tube  14  is provided with a biasing means for urging the pivotable dispensing tube  14  to a closed position. FIGS. 2 and 3 show the dispensing bottle  10  with two preferred embodiments of the biasing means. Referring first to FIG. 2, the dispensing bottle  10  is shown in an exploded view with the pivotable dispensing tube  14  separated from the liquid container  12  to show the details of their construction. The hollow pivot pin  16  which extends from the liquid container  12  has an oval cross section which is slightly larger in the direction of the major axis Y—Y than in the direction of the minor axis X—X. In this embodiment, the Y—Y axis is inclined slightly from vertical. The angle of inclination of the axes is not critical and can be changed to facilitate manufacturability of the dispenser bottle  10  as desired. The pivotable dispensing tube  14  has a transverse pivot hole  18  which has an identical oval cross section to the hollow pivot pin  16 . The major axis Y′—Y′ and the minor axis X′—X′ of the transverse pivot hole  18  are made in the same orientation as the major axis Y—Y and the minor axis X—X of the hollow pivot pin  16  so that the pivotable dispensing tube  14  will slide onto the hollow pivot pin  16  and be stable in the closed position. Preferably, there are a pair of grooves  32 ,  34  molded into the hollow pivot pin  16 , with the first groove  32  at the base of the pin  16  and the second groove  34  near the end of the pin  16 . A pair of corresponding rings  36 ,  38  are molded into the transverse pivot hole  18  so that the pivotable dispensing tube  14  has a snap fit onto the hollow pivot pin  16 . The rings  36 ,  38  fit into the grooves  32 ,  34  and retain the pivotable dispensing tube  14  on the hollow pivot pin  16  while allowing the pivotable dispensing tube  14  to pivot relative to the liquid container  12 . It should be noted that the relative positions of the rings  36 ,  38  and grooves  32 ,  34  can be reversed if desired without affecting the functionality of the dispensing bottle  10 . As noted above, the distal end  26  of the second fluid passage  24  within the pivotable dispensing tube  14  is positioned higher than the proximal end  28 . The discharge port  22  of the first fluid passage  20  through the hollow pivot pin  16  is angled downward so that the proximal end  28  of the second fluid passage  24  is not aligned with the discharge port  22  when the pivotable dispensing tube  14  is in the closed position so that no liquid can pass from the liquid container  12  into the pivotable dispensing tube  14 . When the pivotable dispensing tube  14  is rotated downward relative to the liquid container  12 , the proximal end  28  of the second fluid passage  24  moves into alignment with the discharge port  22 , acting like a valve to allow fluid flow between the first fluid passage  20  and the second fluid passage  24  within the pivotable dispensing tube  14 . 
     As the pivotable dispensing tube  14  rotates downward into the open position, the major axis Y′—Y′ of the oval-shaped transverse pivot hole  18  rotates out of alignment with the major axis Y—Y of the oval-shaped hollow pivot pin  16 . The transverse pivot hole  18  and the hollow pivot pin  16  deform elastically as the pivotable dispensing tube  14  rotates downward, storing elastic energy. When the pivotable dispensing tube  14  is released, the stored elastic energy causes the dispensing tube  14  to rotate upward into the closed position, automatically stopping the flow of liquid through the discharge port  22  into the second fluid passage  24 . Thus, the cooperation between the geometry of the oval-shaped hollow pivot pin  16  and the oval-shaped transverse pivot hole  18  act as a biasing means to urge the pivotable dispensing tube  14  into the closed position so that the closure of the dispensing bottle is self-operating. 
     The dispensing bottle  10  is shown with a second preferred embodiment of the biasing means for urging the pivotable dispensing tube  14  to a closed position in FIGS. 3A-3C. For ease of understanding, the description of this embodiment will use the same reference numbers for parts and features which are closely analogous to those in FIGS. 1A,  1 B,  1 C, and FIG.  2  and will assign new reference numbers to those parts and features which are significantly different. The biasing means in this embodiment has the additional feature of a detent for holding the pivotable dispensing tube  14  stable in the open position while the dispensing bottle  10  is in use. The biasing means of the self-operating closure acts to urge the pivotable dispensing tube  14  to a closed position when the dispensing tube  14  is moved past the detent, either manually or by setting the dispensing bottle  10  down on a horizontal surface. 
     FIG. 3A shows a perspective view of the dispensing bottle  10  with the liquid container  12  and the pivotable dispensing tube  14  assembled together. FIG. 3B shows an enlarged view of the pivotable dispensing tube  14  of the dispensing bottle of FIG.  3 A. FIG. 3C is a partial cross section of the pivotable dispensing tube  14  taken along line  3 C— 3 C in FIG. 3B. A hollow pivot pin  40  extends from the liquid container  12 . The hollow pivot pin  40  has a generally cylindrical geometry with one half of the cylinder being rounded  42  and the other half having three flat sides  44 ,  46 ,  48 . A transverse pivot hole  50  through the pivotable dispensing tube  14  has a matching cylindrical geometry with one half of the cylindrical hole  50  being rounded  52  and the other half having three flat sides  54 ,  56 ,  58 . The discharge port  22  which connects with the first fluid passage  20  is located on the rounded side  42  of the hollow pivot pin  40 . Likewise, the proximal end  28  of the second fluid passage  24  through the pivotable dispensing tube  14  is located on the rounded side  52  of the transverse pivot hole  50 . When the pivotable dispensing tube  14  is rotated downward relative to the liquid container  12 , the proximal end  28  of the second fluid passage  24  moves into alignment with the discharge port  22 , acting like a valve to allow fluid flow between the first fluid passage  20  and the second fluid passage  24  within the pivotable dispensing tube  14 . 
     As the pivotable dispensing tube  14  rotates downward into the open position, the three flat sides  54 ,  56 ,  58  of the transverse pivot hole  50  rotate out of alignment with the flat sides  44 ,  46 ,  48  of the hollow pivot pin  40 . The transverse pivot hole  50  and the hollow pivot pin  40  deform elastically as the pivotable dispensing tube  14  rotates downward, storing elastic energy. When the pivotable dispensing tube  14  reaches the open position, two of the flat sides  54 ,  56  of the hollow pivot pin  40  realign with two of the flat sides  46 ,  48  of the hollow pivot pin  40 , acting as a detent to hold the pivotable dispensing tube  14  in a quasistable open position. With the pivotable dispensing tube  14  in this quasistable open position, the user is free to dispense as much or as little of the liquid contents of the dispensing bottle  10  as is desired. When the user is through dispensing, the self-operating closure is activated by moving the pivotable dispensing tube  14  past the detent position, whereupon the stored elastic energy from the deformation of the transverse pivot hole  50  and the hollow pivot pin  40  causes the dispensing tube  14  to rotate upward into the closed position, automatically stopping the flow of liquid through the discharge port  22  into the second fluid passage  24 . The pivotable dispensing tube  14  can be moved past the detent position either by manually rotating the dispensing tube  14  or by setting the dispensing bottle  10  down on a horizontal surface so that the weight of the dispensing bottle  10  and its contents forces the dispensing tube  14  past the detent position, automatically initiating the action of the self-operating closure. This feature allows for very convenient one-handed operation of the dispensing bottle  10  with its self-operating closure. 
     FIGS. 4A and 4B show a second embodiment of the dispensing bottle  60  of the present invention with the pivotable dispensing tube  64  in the closed position and open position, respectively. In this embodiment, the pivotable dispensing tube  64  is aesthetically integrated into the design of the liquid container  62 . The pivotable dispensing tube  64  withdraws into a recess  70  within the base  72  of the liquid container  62 , which aside from the aesthetic appeal also lends to the drip resistant aspect of the dispensing bottle  60 . The distal end  66  of the pivotable dispensing tube  64  is rounded, which facilitates activation of the automatic closure mechanism when the dispensing bottle  60  is placed on a horizontal surface. An indentation  68  in the upper edge of the pivotable dispensing tube  64  assists the user in gripping the dispensing tube  64  to withdraw it from the recess  70  in the liquid container  62  to open the dispensing bottle  60 . Either of the biasing means discussed above in connection with FIGS. 2 and 3, or other functional equivalents, can be used in conjunction with this design. 
     Alternatively, the biasing means for urging the pivotable dispensing tube  74  into the closed position can be provided by the weight of the dispensing bottle  60  and its contents. To facilitate this gravity-activated self-operating closure mechanism, the dispensing bottle  60  should be provided with a low friction pivoting connection between the pivotable dispensing tube  74  and the liquid container  72  and, when it is in the open position, the pivotable dispensing tube  74  should form an acute angle with respect to the base of the liquid container, as shown in FIG.  4 B. The rounded distal end  66  of the pivotable dispensing tube  64  in this embodiment also assists this gravity-activated self-operating closure action. 
     FIGS. 5A and 5B show a third embodiment of the dispensing bottle  80  of the present invention with the pivotable dispensing tube  84  in the closed position and open position, respectively. In this embodiment, an L-shaped pivotable dispensing tube  84  is integrated into the design of the liquid container  82 . The pivotable dispensing tube  84  withdraws into a recess  90  within the base  92  of the liquid container  82 . In order to facilitate withdrawal of the pivotable dispensing tube  84  from the recess  90  in the liquid container  82  to open the dispensing bottle  80 , a knob or dial  94  is integrated into the pivoting end of the dispensing tube  84 . The dial  94  can be used to open the pivotable dispensing tube  84  manually and any one of the biasing means discussed above in connection with FIGS. 2,  3 ,  4 A and  4 B, or other functional equivalents, can be used to automatically close the dispenser bottle  80  after the desired amount of liquid has been dispensed. 
     FIG. 6A shows a perspective view of a fourth embodiment of the dispensing bottle  100  of the present invention with the dispensing tube  106  incorporated into a disk-shaped rotating dispensing spout  102 . FIG. 6B is a cross section of the dispensing bottle  100  of FIG. 6A taken along the line  6 B— 6 B. The dispensing bottle  100  has a liquid container  120  for holding a liquid to be dispensed. A hollow pivot pin  108  extends from the bottom of the liquid container  120 . A first fluid passage  112  extends through the hollow pivot pin  108  connecting the interior of the fluid container  120  with a discharge port  110  located in the side of the hollow pivot pin  108 . A disk-shaped rotating dispensing spout  102  is rotatably mounted on the bottom of the liquid container  120 . A pivot hole  114  through the disk-shaped rotating dispensing spout  102  engages the hollow pivot pin  108 . A second fluid passage  106  which acts as a dispensing tube extends through the body of the disk-shaped rotating dispensing spout  102  from the pivot hole  114  to a dispensing port  104  on the exterior of the dispensing spout  102 . When the disk-shaped rotating dispensing spout  102  is in the open position, as shown in FIG. 6A, the second fluid passage  106  aligns with the discharge port  110  in the side of the hollow pivot pin  108 . When the disk-shaped rotating dispensing spout  102  is in the closed position, as shown in FIG. 6B, the second fluid passage  106  moves out of alignment with the discharge port  110 , thereby acting like a valve to close off fluid flow between the first fluid passage  112  and the second fluid passage  106 . 
     In a preferred embodiment, the second fluid passage  106  within the disk-shaped rotating dispensing spout  102  is configured so that the second fluid passage  106  is inclined upward from the discharge port  110  on the hollow pivot pin  108  to the dispensing port  104  on the exterior of the dispensing spout  102 . That way, when the dispensing bottle  100  is placed on a level surface, such as a shelf or countertop, any liquid remaining in the second fluid passage  106  tends to flow back into the passage  106  rather than flowing out the open dispensing port  104 . This feature eliminates dripping from the dispensing bottle  100  between uses. 
     The disk-shaped rotating dispensing spout  102  is made self-closing by incorporating a biasing means, such as those described above, into the dispensing bottle  100 . An exemplary embodiment of the disk-shaped rotating dispensing spout  102  incorporating a biasing means is shown in cross section in FIG.  6 B. The hollow pivot pin  108  extending from the bottom of the liquid container  120  is made with a slightly oval cross section. The pivot hole  114  through the disk-shaped rotating dispensing spout  102  is made with an oval cross section which matches the oval shape of the hollow pivot pin  108  when the disk-shaped rotating dispensing spout  102  is in the closed position as depicted by the second fluid passage drawn in solid lines  106 . When the disk-shaped rotating dispensing spout  102  is rotated to the open position, as depicted by the second fluid passage drawn in phantom lines  106 ′, the hollow pivot pin  108  and/or the pivot hole  114  must deform as their oval shapes rotate out of alignment, storing up elastic energy. When the disk-shaped rotating dispensing spout  102  is released, the stored elastic energy causes it to rotate back to the closed position. 
     If desired, a detent to hold the disk-shaped rotating dispensing spout  102  in the open position, such as the one described in connection with FIGS.  3 A— 3 C, may be incorporated into the dispensing bottle  100 . After opening, the disk-shaped rotating dispensing spout  102  will remain in a quasistable open position until the self-operating closure is activated by rotating the dispensing spout  102  past the detent position to release the stored elastic energy which causes the dispensing spout  102  to rotate into the closed position. 
     In another configuration based on the embodiment of FIG. 6A, the hollow pivot pin  108  and the pivot hole  114  are molded with coacting spiral or ramp-shaped cam surfaces that cause the disk-shaped rotating dispensing spout  102  to move downward from the liquid container  120  as it is rotated to the open position. Thus, the center of gravity of the dispensing bottle  100  is slightly elevated when the disk-shaped rotating dispensing spout  102  is in the open position, thereby storing potential energy. In addition, the hollow pivot pin  108  and/or the pivot hole  114  may deform as the disk-shaped rotating dispensing spout  102  rotates to store up elastic energy as well. A detent molded into the hollow pivot pin  108  and the pivot hole  114  holds the disk-shaped rotating dispensing spout  102  in the open position. When the dispensing bottle  100  is placed on a horizontal surface, the weight of the dispensing bottle  100  and its contents forces the disk-shaped rotating dispensing spout  102  past the detent position to release the stored potential and/or elastic energy which causes the dispensing spout  102  to rotate into the closed position. 
     The dispensing bottle embodiment of FIGS. 6A-6B has an additional advantage in that the center of gravity of the liquid container  120  is always over the supporting bottom surface  116  of the disk-shaped rotating dispensing spout  102  in the open and closed positions, lending to the stability of the dispensing bottle  100 . 
     FIG. 6C shows a perspective view of a variation of the fourth embodiment  130 . The dispensing spout  102  is of a similar configuration to the basic dispensing bottle  100 . However, the dispensing spout  102  is a separate cap  132  which may be screwed onto the threaded neck  134  of a standard bottle. This allows the cap  132  to be installed onto a standard bottle to convert the bottle into a bottom dispensing design. 
     A fifth embodiment of the dispensing bottle  210  of the present invention is shown in FIGS. 7A and 7B. The dispensing bottle  210  has a liquid container  212  molded of a flexible plastic material for holding a liquid. A pivotable dispensing cap  214  is pivotably attached to the mouth  216  of the liquid container  212 , which is preferably located at the bottom of the liquid container  212 . The mouth  216  of the liquid container  212  is shaped with a ridge around it forming, at the back edge, a heel  218  and, at the front edge, a toe  220 . Above the toe  220  on the front edge of the mouth  216  of the liquid container  212  is a second ridge forming a male detent  222 . 
     The pivotable dispensing cap  214  is formed with a recess  224  that is shaped to sealingly engage the mouth  216  of the liquid container  212 . The recess  224  has an internal groove  226  which engages the heel  218  and the toe  220  on the mouth  216  of the liquid container  212  when the pivotable dispensing cap  214  is in the closed position, as shown in FIG.  7 A. Above the internal groove  226  is a second groove forming a female detent  228  which, in the closed position, engages the male detent  222  on the mouth  216  of the liquid container  212 . The pivotable dispensing cap  214  has a fluid passage  230  which is preferably inclined upward so that any liquid remaining in the fluid passage  230  after dispensing tends to flow back into the fluid passage  230  to prevent dripping from the dispensing bottle  210  between uses. When the pivotable dispensing cap  214  is in the closed position as shown in FIG. 7A, the mouth  216  of the liquid container  212  is sealed by the bottom  236  of the recess  224  and the fluid passage  230  is sealed by the toe  220  on the mouth  216  of the liquid container  212 . Optionally, the recess  224  within the pivotable dispensing cap  214  may include a raised annular seal (not shown) or other feature to securely seal the mouth  216  of the liquid container  212  in the closed position. 
     When the pivotable dispensing cap  214  is pivoted to the open position as shown in FIG. 7B, the toe  220  on the mouth  216  of the liquid container  212  engages the female detent  228  within the recess  224  of the pivotable dispensing cap  214  and the fluid passage  230  is open so that liquid can flow from the mouth  216  of the liquid container  212  and out the fluid passage  230 . The pivotable dispensing cap  214  can be pivoted to the open position by pressing on the tail  232  which extends from the back of the pivotable dispensing cap  214 . The desired amount of liquid can then be dispensed by squeezing the flexible liquid container  212 . After dispensing, the pivotable dispensing cap  214  can be closed by pressing on the nose  234  of the pivotable dispensing cap  214  which is under the discharge end of the fluid passage  230 . Optionally, the dispensing bottle  210  may include a locking mechanism to prevent the pivotable dispensing cap  214  from being inadvertently pivoted to the open position during storage or transport. In addition, the dispensing bottle  210  may also include a biasing means for urging the pivotable dispensing cap  214  into the closed position, as described above in connection with the other embodiments of the invention. 
     A sixth embodiment of the dispensing bottle  310  of the present invention is shown in FIGS. 8A and 8B. The dispensing bottle  310  has a liquid container  312  molded of a flexible plastic material for holding a liquid. A pivotable dispensing cap  314  is pivotably attached to the mouth  316  of the liquid container  312 , which is preferably located at the bottom of the liquid container  312 . Attached to the mouth  316  of the liquid container  312  is a pivot  322  in the shape of a sphere or, alternatively, a cylinder. The spherical or cylindrical pivot  322  may be molded integrally with the liquid container  312  or it may be molded as a separate piece which screws onto the mouth  316  of the liquid container  312 . A first fluid passage  318  connects to the mouth  316  of the liquid container  312  and discharges from the spherical or cylindrical pivot  322 . A raised O-ring seal  320  surrounds the discharge opening of the first fluid passage  318 . Preferably, the raised O-ring seal  320  is integrally molded with the spherical or cylindrical pivot  322  on the mouth  316  of the liquid container  312 . 
     The pivotable dispensing cap  314  is formed with a recess  324  that is shaped to have a snap fit with the spherical or cylindrical pivot  322  on the mouth  316  of the liquid container  312 . The pivotable dispensing cap  314  has a second fluid passage  330  which is preferably inclined upward so that any liquid remaining in the fluid passage  330  after dispensing tends to flow back into the fluid passage  330  to prevent dripping from the dispensing bottle  310  between uses. When the pivotable dispensing cap  314  is in the closed position as shown in FIG. 8A, the interior surface of the recess  324  sealingly engages the raised O-ring seal  320  on the spherical or cylindrical mouth  316 , preventing any liquid from flowing out of the liquid container  312 . 
     When the pivotable dispensing cap  314  is pivoted to the open position as shown in FIG. 8B, the second fluid passage  330  in the pivotable dispensing cap  314  aligns with the first fluid passage  318  in the spherical or cylindrical pivot  322  so that liquid can flow from the mouth  316  of the liquid container  312  and out the fluid passage  330 . The pivotable dispensing cap  314  can be pivoted to the open position by pressing on the tail  332  which extends from the back of the pivotable dispensing cap  314 . The desired amount of liquid can then be dispensed by squeezing the flexible liquid container  312 . After dispensing, the pivotable dispensing cap  314  can be closed by pressing on the nose  334  of the pivotable dispensing cap  314  which is under the discharge end of the fluid passage  330 . Optionally, the dispensing bottle  310  may include a detent or locking mechanism to prevent the pivotable dispensing cap  314  from being inadvertently pivoted to the open position during storage or transport. In addition, the dispensing bottle  310  may also include a biasing means for urging the pivotable dispensing cap  314  into the closed position, as described above in connection with the other embodiments of the invention. 
     FIG. 8C shows an exploded view of a variation of the sixth embodiment  340 . The fluid passage  330  is of a similar configuration to the basic dispensing bottle  310 . However, the fluid passage  330  is a separate cap  346  which may be screwed onto the threaded portion  342  of a neck  344  of a standard bottle. This allows the cap  346  to be installed onto a standard bottle to convert the bottle into a bottom dispensing design. Other methods may also be used to install the cap  346  onto a bottle, for example snapon caps or other mechanical interference fits may be used for this and other embodiments. 
     FIGS. 9A,  9 B and  9 C illustrate the one-handed operation of the fifth embodiment of the dispensing bottle  210  which is shown in FIGS. 7A and 7B. The following operational description is equally applicable to the sixth embodiment of the dispensing bottle  310  which is shown in FIGS. 8A and 8B. 
     Between uses, the dispensing bottle  210  of the present invention is stored in an inverted position with the pivotable dispensing cap  214  resting on a horizontal surface so that the liquid contained will settle into the mouth  216  of the liquid container  212  by gravity. To operate the dispensing bottle  210 , the user grasps the liquid container  212  and lifts the dispensing bottle  210 , then pushes the tail  232  which extends from the back of the pivotable dispensing cap  214  down onto a stationary surface  250 , such as a countertop, a sink or a shelf, as shown in FIG.  9 A. This pivots the pivotable dispensing cap  214  to the open position. The desired amount of liquid can then be dispensed by squeezing the flexible liquid container  212 , as shown in FIG.  9 B. When a sufficient amount of liquid has been dispensed, the pivotable dispensing cap  214  is reclosed by pressing on the nose  234  of the pivotable dispensing cap  214 , which is under the discharge end of the fluid passage  230 , down onto the stationary surface  250 , as shown in FIG.  9 C. This pivots the pivotable dispensing cap  214  back to the closed position. Because the fluid passage  230  in the pivotable dispensing cap  214  is inclined upward any liquid remaining in the fluid passage  230  after dispensing tends to flow back into the fluid passage  230  to prevent dripping from the dispensing bottle  210  between uses. 
     Although the examples given include many specificities, they are intended as illustrative of only some of the possible embodiments of the invention. Other embodiments and modifications will, no doubt, occur to those skilled in the art. For example, although the various detailed embodiments of the invention have been described as integrating the self-operating closure into the bottom of an upstanding container, it is also envisioned that the various features of the self-operating closure can be integrated into the cap of a self-standing squeeze tube container or other inverted container to achieve the same function. Although only two of the embodiments have been shown with the closure as a separate cap, other embodiments could also be modified in this manner. Thus, the examples given should only be interpreted as illustrations of some of the preferred embodiments of the invention, and the full scope of the invention should be determined by the appended claims and their legal equivalents.