Abstract:
A water level sensor switch installed in a sidewall of a water tank for detecting its water level is disclosed to include a housing having two bearing portions clamped on two opposite sides of the sidewall of the water tank and a tightening up screw fastened to a vertical wall at a different plane relative to the bearing portions and stop against the sidewall of the water tank to affix the housing to the water tank, a micro switch mounted in the housing, and a float connected to a switching lever of the micro switch outside the housing for biasing the switching lever up and down subject to the level of water in the water tank.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to sensor switch technology and more particularly, to a water level sensor switch for use in a water tank for detecting the level of water in the water tank. 
     2. Description of the Related Art 
     A regular air conditioner system, either of a cooler design or a cold and warm air-conditioning design, generally has a condenser water piping adapted for guiding condensed water to a water tank. Further, a refrigeration equipment, such as freezer or refrigerator, generally uses a water tank to collect condensed water and a water level sensor switch mounted in the water tank for switching on an electric motor to pump water out of the water tank for drainage when the water level reaches a predetermined upper limit position. 
     A conventional water level sensor switch for use in an air conditioner system or refrigeration equipment is known comprising a micro switch, a swinging frame and a float made of polystyrene foam. The micro switch includes an actuation lever that is coupled to the swinging frame. The float is connected to a hook of the swinging frame. When the level of water in the water tank reaches the predetermined full water level position, the float rises, causing the micro switch to start up the electric motor, and therefore the electric motor starts pumping water. When the level of water in the water tank drops below the predetermined low water level position, the float drops down, causing the micro switch to switch off the electric motor, and therefore the electric motor stops from pumping water. 
     However, the aforesaid prior art water level sensor switch cannot be firmly secured to the water tank. When the water level reaches the full water level position, the swinging frame may be forced to tilt by the oscillating water surface, affecting the water level sensing operation. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished to eliminate the drawbacks of the aforesaid prior art designs. It is the main object of the present invention to provide a water level sensor switch, which can be firmly secured to a water tank for detecting the level of water in the water tank accurately. 
     It is another object of the present invention to provide a water level sensor switch, which allows adjustment of the position of the float to fit different application requirements. 
     To achieve these and other objects of the present invention, a water level sensor switch installed in a sidewall of a water tank and adapted for detecting the level of water in said water tank, comprising a housing fastened to the sidewall of the water tank, a micro switch mounted in the housing, and a float. The housing comprises two bearing portions arranged on one same plane at the bottom side thereof and kept apart from each other at a predetermined distance, a vertical wall spaced from the two bearing portions at a predetermined distance and at a different plane, and a tightening up screw driven through the vertical wall for stopping against the sidewall of the water tank to affix the housing to the water tank after the two bearing portions have been clamped on two opposite sides of the sidewall of the water tank. The micro switch comprises a switch body mounted in the housing and a switching lever pivotally coupled to the switch body and extending out of the housing and biasable up and down relative to the housing. The float is connected to one end of the switching lever outside the housing. 
     During installation, the two bearing portions of the housing are clamped on two opposite sides of the sidewall of the water tank, and then the tightening up screw is fastened tight and stopped against the sidewall of the water tank, achieving three-point fixation, and therefore the water level sensor switch is firmly secured to the water tank for detecting the level of water in the water tank accurately. 
     Further, the housing comprises a front cover shell, a rear cover shell fastened to the front cover shell, and an accommodation chamber surrounded by the front cover shell and the ear cover shell. 
     Further, the rear cover shell comprises three locating pins numbered from 1 st  through 3 rd  and suspending in the accommodation chamber. The switch body of the micro switch comprises two locating holes adapted for receiving the first two locating pins or the last two locating pins of the rear cover shell selectively so that the float can be held in one of two alternative positions subject to different application requirements. 
     Further, the rear cover shell comprises two hook rods suspending in the accommodation chamber for hooking up the switch body of the micro switch, enhancing micro switch mounting stability. 
     Further, the front cover shell comprises a rib. Further, the rear cover shell comprises a top wall covered by the front cover shell, and a groove located on an end edge of the top wall for the passing of the rib. The rib can be a tapered rib having a diameter increasing gradually from the bottom side of the front cover shell toward the top side thereof. 
     Further, the front cover shell comprises a pressure strip for stopping against the switch body of the micro switch. Further, the rear cover shell comprises a top wall covered by the front cover shell, and a notch located on an end edge of the top wall for the passing of the pressure strip. 
     Further, an anti-slip member is disposed in the housing and set between the vertical wall and each of the two bearing portions of the housing for stopping against the sidewall of the water tank to avoid slipping. Further, the anti-slip member can be made of sponge or rubber. 
     Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view of a water level sensor switch in accordance with the present invention. 
         FIG. 2  is an exploded view of the water level sensor switch in accordance with the present invention. 
         FIG. 3  is an elevational view of a part of the present invention, illustrating the configuration of the front cover shell. 
         FIG. 4  is an elevational view of a part of the present invention, illustrating the configuration of the rear cover shell. 
         FIG. 5  is a schematic front view of the present invention, illustrating one positioning status of the float and the relationship between the float and the micro switch (the front cover shell of the housing excluded). 
         FIG. 6  is similar to  FIG. 5 , illustrating another positioning status of the float. 
         FIG. 7  is a schematic elevational view of the present invention, illustrating the water level sensor switch installed in a sidewall of a water tank. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     It is to be noted that the directional adjectives used in the specification, such as, front, rear, up, down, top, bottom and the likes are based on drawing directions. 
     At first, please refer to  FIG. 1  and  FIG. 2 . a water level sensor switch  10  in accordance with the present invention comprises a housing  20 , a micro switch  30  mounted inside the housing  20 , and a float  40  connected to the micro switch  30 . 
     As shown in  FIG. 1  and  FIG. 4 , the housing  20  comprises two bearing portions  201  outwardly downwardly extended from the outer surface thereof at one side, a vertical wall  203  kept away from the bearing portions  201  at a predetermined distance and at a different elevation, and a tightening up screw  205  driven through the vertical wall  203 . In this embodiment, these two bearing portions  201  are respectively made in the form of a lug. However, this design is not a limitation. For example, these two bearing portions  201  can be two raised portions located on an extension wall that extends downwardly from the outer surface of the housing  20 . 
     Referring to  FIG. 2  again, the micro switch  30  comprises a switch body  31  accommodated in the housing  20 , and a switching lever  33  extended from the switch body  31  to the outside of the housing  20  and biasable up and down relative to the switch body  31 . 
     The float  40  can be, for example, but not limited to, a hollow plastic cylinder floatable on water. The float  40  is connected with the switching lever  33  in such a manner that the switching lever  33  is biasable up and down subject to the elevation of the float  40 . 
     During application, as shown in  FIG. 7 , the water level sensor switch  10  is installed in a water tank  50  by: clamping the two bearing portions  201  and the vertical wall  203  on two opposing sides of one sidewall  51  of the water tank  50  and then fastening tight the tightening up screw  205  to stop the tip of the tightening up screw  205  against the sidewall  51  of the water tank  50 . Thus, the water level sensor switch  10  is firmly secured to the water tank  50  by three-point fixation and can accurately detect the level of water in the water tank  50  without vibration. 
     Referring to  FIGS. 1 and 4  again, the water level sensor switch  10  further comprises two anti -slip members  60  that are respectively mounted at the two bearing portions  201  in this embodiment for positive stoppage against the sidewall  51  of the water tank  50  to prevent displacement of the housing  20  relative to the water tank  50 . However, the quantity and installation location of the anti-slip members  60  are not limited to this example. For example, in an alternate form, the anti-slip member(s) can be arranged around the bearing portions  201  and the vertical wall  203  or can include only one anti-slip member  60  mounted on one bearing portion  201 . Further, the anti-slip members  60  can be, but not limited to, sponge or rubber. 
     Referring to  FIG. 2 , the housing  20  consists of a front cover shell  21  and a rear cover shell  23 . The front cover shell  21  and the rear cover shell  23  define an accommodation chamber  25 . 
     Referring to  FIG. 3 , the front cover shell  21  comprises two tapered ribs  211  arranged in parallel that have a diameter gradually reducing in direction from the bottom side toward the top side, and two pressure strips  213  respectively disposed at an outer side relative to the tapered ribs  211 . 
     Referring to  FIG. 4 , the rear cover shell  23  comprises a top wall  231 . The top wall  231  has two grooves  233  and two notches  235  on one end thereof for the passing of the two tapered ribs  211  and the two pressure strips  213  respectively. When assembling the front cover shell  21  and the rear cover shell  23 , the tapered ribs  211  and the grooves  233  facilitate quick positioning and installation. By means of pressing the pressure strips  213  against the micro switch  30 , the micro switch  30  is firmly held in the housing  20 . It is to be understood that the quantity and configuration of the pressure strips  213  are not limited the aforesaid design. Any quantity that achieves quick positioning is acceptable. The tapered design simply facilitates insertion of the ribs through the grooves  233 . 
     Referring to  FIG. 4  again, the rear cover shell  23  further comprises three locating pins numbered 1 st  through 3 rd    26 ˜ 28 . The 2 nd  locating pin  27  is disposed in a diagonal manner relative to the 1 st  locating pin  26  and the 3 rd  locating pin  28 . Further, multiple hook rods  29  are located on the inner surface of the rear cover shell  23 . 
     Referring to  FIGS. 5 and 6  and  FIG. 2  again, the switch body  31  of the micro switch  30  has two locating holes  311  respectively disposed in two diagonal corners thereof for receiving the locating pins  26 ˜ 28  selectively. 
     During installation, as shown in  FIGS. 5 and 6 , the switch body  31  of the micro switch  30  is set in the accommodation chamber  25  and hooked in place by the two hook rods  29  to hold the switching lever  33  outside the housing  20 . At this time, the switching lever  33  has its one end pivotally connected to the switch body  31  and its other end connected to the float  40 . During application, the switching lever  33  will be moved up and down with the float  40  subject to the level of water in the water tank  50  to trigger or not to trigger the micro switch  30 . Further, by means of selectively plugging the 1 st  and 2 nd  locating pins  26  and  27  or the 2 nd  and 3 rd  locating pins  27  and  28  into the locating holes  311  of the switch body  31 , the position of the float  40  is relatively changed to fit different application requirements. 
     The water level sensor switch  10  is practical for use in an air conditioning system or refrigeration system. After installation of the water level sensor switch  10  in the water tank  50  of an air conditioning system or refrigeration system, the float  40  will float on the water in the water tank  50 . When the water level elevates to about the full water level (upper limit position), the float  40  rises to carry the switching lever  33  upwards, causing the micro switch  30  to trigger the actuation button  35  in starting up an electric motor (not shown) to pump water. When the water level in the water tank  50  is lowered to about the predetermined low water level (lower limit position), the float  40  drops down to carry the switching lever  33  downwards, thereby releasing the actuation button  35 , and therefore the electric motor is off and stopped from pumping water. The invention can also be used in a water reservoir  50 . When the float rises  40  subject to an increase in the water level, the switching lever  33  is turned upwards to trigger the actuation button  35 , stopping an electric motor (not shown) from pumping water into the water reservoir  50 . 
     In conclusion, by means of stopping the tightening up screw  203  against the sidewall of the water tank  50 , the two bearing portions  201  and the tightening up screw  203  establish a three-point fixation mechanism to firmly secure the water level sensor switch  10  to the water tank  50 . Thus, the water level sensor switch  10  will not be forced to vibration by the water level during operation and can accurately detect the level of water in the water tank  50 . Further, the position of the float  40  of the by the water level sensor switch  10  can be adjusted to fit different application requirements. 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.