Abstract:
An automatic replenishing mechanism for a pet drinking fountain is a container having a water injection element, a float, a linkage set, and a sealing plug. The water injection element, connected to the container, has a water inlet and a base. The float, connected by a link bar to the base, is located underneath the water inlet and limited by a guiding portion to float longitudinally. The sealing plug is mounted on the link bar near the water inlet. When water level rises to elevate the float, the link bar rotates to push the sealing plug. When the float floats to a predetermined level, the sealing plug blocks the water inlet to stop water supply. When a pet drinks water and the water level drops, the float sinks from the predetermined level. The link bar rotates to retreat the sealing plug from the water inlet, thereby automatically replenishing water.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The invention relates to a pet drinking fountain and, in particular, to an auto water replenishing mechanism of the pet drinking fountain. 
     2. Related Art 
     In addition to feeding food, one also needs to supply water for his pet. Traditionally, pet drinking water supply is usually a simple container filled with water. The container can be either closed or open. The size and shape of the container also vary from pet to pet. Such containers simply hold water. On the market, there starts to have containers with cycling water. They mainly utilize a pump to yank up pressure, thereby facilitating dynamical circulation of water. Many pet owners think that such water is good for their pets. However, regardless of what type of container, the pet owner has to take notice when water level is low and resupply the water. Otherwise, the pet will be short of drinking water. Those with pump circulation will further face the problem that the pump motor may fail because of the water shortage. 
       FIG. 12  shows a pet drinking fountain that can automatically replenish water. Its structure mainly has a water injection element  91  on the container  90  thereof. During water supply, water is injected into the container  90  by a water inlet  910 . The water injection element is pivotally provided with a horizontal swing arm  92 , whose end is connected with a float  93 . The swing arm  92  urges against a sealing plug  94  in the water injection element. The float  93  swings with respect to the pivotal point of the swing arm  92  on the water injection element. When the water level rises, the float rises and drives the swing arm to push the sealing plug  94  to block water inlet  910 . When the float drops, the sealing plug  94  retreats from the water inlet  910 . 
     However, the above-mentioned pet drinking fountain with automatic water replenishment has the following problems: 
     1. The swing arm  92  must have a certain length, so that the swing arm  92  can push the sealing plug  94  to block the water inlet  910  as the float  93  rises with the water level according to the lever principle. Thus, the size of container must be larger than the extended length of the swing arm  92  and the float  93 . It is then difficult to reduce the size. Therefore, it is usually used in larger pet drinking fountains. Small pet drinking fountains do not enjoy the function of automatic water replenishment. 
     2. Since water sources in different regions have different pressures, floats  93  of the same size and swing arm  92  of the same length may have different pushing forces on the sealing plug  94  during the process of replenishing water in the container  90 . In a region with larger water pressure, the water inlet may not be completely blocked, resulting in failure of automatic water replenishment. 
     Therefore, it is the goal of the invention to solve the above-mentioned problems in conventional pet drinking fountains. 
     SUMMARY OF THE INVENTION 
     Objects 
     An objective of the invention is to provide an auto water replenishing mechanism for pet drinking fountains. It is disposed in a container filled with water for a pet to drink. Through a careful design, the space required for the float and the link bar is reduced so that only a small container is needed to accommodate the float and the link bar. Therefore, the invention can be used in a small pet drinking fountain to provide the function of automatic water replenishment. Besides, a linkage set is employed between the float and the sealing plug to overcome the problem due to regions with different water pressures. When water is injected from a source with a larger pressure, the linkage set provides the sealing plug with sufficient resistance to completely block the incoming water. This prevents the sealing plug from failure. 
     To achieve the above-mentioned objective, the invention includes: 
     a water injection element connected to a container and exposed from a water outlet connected to a water source, and having a water inlet for injecting water into the container and a base; 
     a float disposed under the water inlet of the water injection element and limited by a guiding portion to float longitudinally on water; 
     a linkage set composed of at least two link bars pivotally connected on two ends and linking between the base and the float; and 
     a sealing plug mounted on the link bar in the vicinity of the water inlet of the water injection element; 
     wherein when water level rises, the float floats to swing the link bar and drive the sealing plug; when the float floats to a predetermined level, the sealing plug is driven to block the water inlet, preventing water from further flowing into the container; when a pet drinks water and lowers the water level, the float sinks from the predetermined level to swing the link bar and retreat the sealing plug from the water inlet, thereby automatically replenishing water. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects and advantages of the invention will become apparent by reference to the following description and accompanying drawings which are given by way of illustration only, and thus are not limitative of the invention, and wherein: 
         FIG. 1  is a three-dimensional view of the first embodiment of the invention, showing the base, the float, the sealing plug, and the linkage set of the auto water replenishing mechanism; 
         FIG. 2  is a schematic cross-sectional view of the auto water replenishing mechanism in the first embodiment, showing that the sealing plug retreats from the water inlet for water replenishment as the float drops; 
         FIG. 3  is a schematic cross-sectional view of the auto water replenishing mechanism in the first embodiment, showing that the sealing plug blocks the water inlet as the float rises; 
         FIG. 4  is a three-dimensional view of the second embodiment of the auto water replenishing mechanism in a pet drinking fountain; 
         FIG. 5  is a three-dimensional view of the second embodiment of the invention, showing the base, the float, the sealing plug, and the linkage set of the auto water replenishing mechanism; 
         FIG. 6  is a schematic cross-sectional view of the auto water replenishing mechanism in the second embodiment, showing that the sealing plug retreats from the water inlet for water replenishment as the float drops; 
         FIG. 7  is a schematic cross-sectional view of the auto water replenishing mechanism in the second embodiment, showing that the sealing plug blocks the water inlet as the float rises; 
         FIG. 8  is a three-dimensional view of the third embodiment of the auto water replenishing mechanism in a pet drinking fountain; 
         FIG. 9  is a three-dimensional view of the third embodiment of the invention, showing the base, the float, the sealing plug, and the linkage set of the auto water replenishing mechanism; 
         FIG. 10  is a schematic cross-sectional view of the auto water replenishing mechanism in the third embodiment, showing that the sealing plug retreats from the water inlet for water replenishment as the float drops; 
         FIG. 11  is a schematic cross-sectional view of the auto water replenishing mechanism in the third embodiment, showing that the sealing plug blocks the water inlet as the float rises; and 
         FIG. 12  is a schematic cross-sectional view of a conventional auto water replenishing mechanism for a pet drinking fountain. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements. 
     This embodiment of the invention provides an auto water replenishing mechanism for a pet drinking fountain. As shown in  FIG. 1 , it is installed in a container  1 . The container  1  in this embodiment is a small cup. The disclosed auto water replenishing mechanism includes a water injection element  2 , a float  3 , a sealing plug  4 , and a linkage set. 
     As shown in  FIGS. 2 and 3 , the container  1  has a surrounding wall  10  that encloses a chamber  11 . The chamber  11  has an upward opening  12  on the surrounding wall  10 . The water injection element  2  is disposed at the opening  12  of the surrounding wall  10 . 
     As shown in  FIGS. 2 and 3 , the water injection element  2  has a water outlet  20  and a water inlet  21  and a base  22 . The base  22  in this embodiment can be separated from the water injection element  2 . The base  22  has two long holes  220  opened on two opposite sides. One end of the long holes has a first pivotal connection part  221 , and the other end has a second pivotal connection part  222 . 
     As shown in  FIGS. 2 and 3 , the float  3  is located right underneath the base  22  and inside the chamber  11 . The surrounding wall  10  functions as a guiding portion. The top of the float  3  has a third pivotal connection part  30  on the same side as the first pivotal connection part  221 . The third pivotal connection part  30  has a long groove  300  through from both sides. 
     As shown in  FIGS. 2 and 3 , the linkage set in this embodiment includes a first link bar  5  and a second link bar  6 . The first link bar is above the base  22  and pivotally connected to the first pivotal connection part  221  on one end. One end of the second link bar  6  extends via the two long holes  220  to above the base  22  and is pivotally connected to the second pivotal connection part  222 . The ends of the first link bar  5  and the second link bar  6  at the second the pivotal connection part  222  are pivotally connected together. The end of the second link bar  6  below the base  22  can slide horizontally within the long groove  300  of the third pivotal connection part  30 . 
     As shown in  FIGS. 2 and 3 , the sealing plug  4  is mounted on the end of the first link bar  5  at the first pivotal connection part  221 . The sealing plug  4  is right underneath the water inlet  21 . One end of the second link bar  6  is driven by the longitudinal motion of the float  3  to swing along the long groove  300  of the third pivotal connection part  30 . The first link bar  5  is driven to swing and displace the sealing plug  4  longitudinally. The sealing plug  4  rises to block the water inlet  21 , preventing water from flowing into the container  1 . On the other hand, when a pet drinks water and lowers the water level, the float  3  drops to pull the second link bar  6  and the first link bar  5 . The sealing plug  4  lowers and retreats from the water inlet  21 , achieving the effect of automatic water replenishment. 
     An advantage of the invention is the following. The water injection element  2  is above the float  3 . The two are connected via the first link bar  5  and the second link bar  6 . As the float  3  moves, its relative distance to the water injection element  2  only changes in the longitudinal direction. Therefore, the required space is simply the longitudinal depth of water inside the container  1 . The transverse space of the swing arm  92  and the float  93  in a conventional pet drinking fountain can be neglected. In comparison with the prior art, the invention allows more space for water in the container of the same size. This reduction in size also enables smaller containers to use the disclosed auto water replenishing mechanism, enjoying the same function of automatic water replenishment. 
     Besides, the base  22  and the float  3  are connected via the linage set. Therefore, the pushing force imposed on the sealing plug  4  is better than the case with a single link bar. It overcomes the problem associated with different water pressures in different regions. In other words, even if water pressure varies, the linkage set still enables the sealing plug  4  to have sufficient pushing force to block the water inlet  21  of the water injection element  2 . 
     Of course, the invention has many other embodiments that only differ in details. Please refer to  FIGS. 4 to 7  for a second embodiment of the invention. As shown in  FIG. 4 , it is installed in a container  1 A which in this embodiment is a small bowl. The auto water replenishing mechanism in this embodiment includes a water injection element  2 A, a float  3 A, a sealing plug  4 A, and a linkage set. 
     As shown in  FIGS. 5 and 6 , a water outlet  20 A of the water injection element  2 A is connected in tandem with a base  22 A. The bottom of the base  22 A has a standing post  220 A, both sides of which are formed with a first pivotal connection part  221 A and a second pivotal connection part  222 A. The first pivotal connection part  221 A is closer to the water outlet  20 A, while the second pivotal connection part  222 A is farther from the water outlet  20 A. 
     As shown in  FIGS. 5 and 6 , the float  3 A is right underneath the base  22 A. The center of the float  3 A has a through hole  30 A for the standing post  220 A to go in. The standing post  220 A in this embodiment is the guiding portion of the float  3 A. The top of the float  3 A has a third pivotal connection part  31 A on the same side as the first pivotal connection part  221 A. The third pivotal connection part  31 A has a long groove  310 A through from both sides. 
     As shown in  FIGS. 5 and 6 , the linkage set of this embodiment includes a first link bar  5 A and a second link bar  6 A. One end of the first link bar  5 A pivotally connects to the first pivotal connection part  221 A. One end of the second link bar  6 A pivotally connects to the second pivotal connection part  222 A. The other end of the second link bar  6 A can horizontally slide within the long groove  310 A of the third pivotal connection part  31 A. The ends of the first link bar  5 A and the second link bar  6 A at the second pivotal connection part  222 A are pivotally connected together. 
     As shown in  FIGS. 6 and 7 , the sealing plug  4 A is mounted on the end of the first link bar  5 A toward the first pivotal connection part  221 A. The sealing plug  4 A is right underneath the water inlet  21 A. One end of the second link bar  6 A is driven to swing within the long groove  310 A of the third pivotal connection part  31 A by the longitudinal motion of the float  3 A. The first link bar  5 A is driven to swing, pushing the sealing plug  4 A to move longitudinally. The sealing plug  4 A thus rises to block the water inlet  21 A, preventing water from flowing into the container  1 A. On the other hand, as a pet drinks water to lower the water level, the float  3 A drops to pull the second link bar  6 A and the first link bar  5 A. The sealing plug  4 A lowers and retreats from the water inlet  21 A, achieving the effect of automatic water replenishment. 
     The auto water replenishing mechanism in this embodiment differs from the first embodiment in various components. However, it shares some common features as the first embodiment. That is, this embodiment also has the water injection element  2 A above the float  3 A. The base  22 A and the float  3 A are also connected via the linkage set, thereby achieving the same effect as the first embodiment. 
     Please refer to  FIGS. 8 to 11  for a third embodiment of the invention. As shown in  FIG. 8 , it is installed in a container  1 B which is also a small bowl as in the second embodiment. The auto water replenishing mechanism in this embodiment includes: a water injection element  2 B, a float  3 B, a sealing plug  4 B, and a linkage set. 
     As shown in  FIGS. 9 and 10 , a water outlet  20 B of the water injection element  2 B is connected with a base  22 B in tandem. The bottom of the base  22 B has a standing post  220 B, both sides of which are formed with a first pivotal connection part  221 B and a second pivotal connection part  222 B. The first pivotal connection part  221 B is closer to the water outlet  20 B, while the second pivotal connection part  222 B is farther from the water outlet  20 B. 
     As shown in  FIGS. 9 and 10 , the float  3 B is right underneath the base  22 B. The center of the float  39  has a through hole  30 B for the standing post  220 B to enter. The standing post  220 B in this embodiment is the guiding portion of the float  3 B. The top of the float  3 B has a third pivotal connection part  31 B on the same side as the first pivotal connection part  221 B. The third pivotal connection part  31 B has a long groove  310 B through on both sides. 
     As shown in  FIGS. 9 and 10 , this embodiment has a first link bar  5  whose one end pivotally connects to the first pivotal connection part  221 B and a second link bar  6  whose one end pivotally connects to the second pivotal connection part  222 B. The other end of the second link bar  6 B can slide horizontally within the long groove  310 B of the third pivotal connection part  31 B. The ends of the first link bar  5 B and the second link bar  6 B at the second pivotal connection part  222 B are pivotally connected together. 
     As shown in  FIGS. 10 and 11 , the sealing plug  4 B is mounted on the end of the first link bar  5 B toward the first pivotal connection part  221 B. The sealing plug  4 B is on a side of the water inlet  21 B. One end of the second link bar  6 B is driven to swing within the long groove  310 B of the third pivotal connection part  31 B by the longitudinal motion of the float  3 B. The first link bar  5 B is driven to swing, thereby driving the sealing plug  4 B to move transversely. The sealing plug  4 B thus moves sideways to block the water inlet  21 B, preventing water from flowing into the container  1 B. On the other hand, as a pet drinks water to lower the water level, the float  3 B drops to pull the second link bar  6 B and the first link bar  5 B. The sealing plug  4 B then moves sideways and retreats from the water inlet  21 B, achieving the effect of automatic water replenishment. 
     Although the auto water replenishing mechanism in this embodiment differs from the first and second embodiments in various components, it shares the following common features. This embodiment also has the water injection element  2 B above the float  3 B. The base  22 B and the float  3 B are connected via the linkage set as well. This embodiment still achieves the same effect as the first and second embodiments. 
     Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to people skilled in the art. Therefore, it is contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.