Abstract:
The present invention provides an ice storage detection switch for detecting an ice level in an ice storage chamber of an ice making machine including: a magnet lever rotatably fitted to the switch lever, for holding the magnet so that the magnet is located in a vicinity of the reed switch when the switch lever is not pressed; and a projecting portion formed on the switch case to be located between a rotational center of the magnet lever and the reed switch, the magnet separating from the reed switch through abutment of the magnet lever on the projecting portion and rotation of the magnet lever when the switch lever is pressed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to an ice storage detection switch, and more particularly to a switch for detecting an ice level in an ice storage chamber of an ice making machine.  
         [0003]     2. Description of the Related Art  
         [0004]     In an ice making machine for storing blocks of ice produced by an ice making portion in an ice storage chamber, an ice storage detection switch as shown in, for example,  FIG. 5  is installed in the ice storage chamber. This ice storage detection switch is intended to detect the ice level in the ice storage chamber and stop operation of the ice making machine. In this ice storage detection switch, a switch lever  2  is rotatably fitted about a rotational center  3  on the ice storage chamber side of a switch case  1  fixed to a wall surface or the like of the ice making chamber (e.g., see Japanese Utility Model Application Laid-open No. 1-151177).  
         [0005]     As shown in  FIG. 6   a , in the switch case  1 , a reed switch  5  is embedded in a reed switch holding portion  4  formed protrusively toward the switch lever  2 . On the other hand, a magnet lever  6  is rotatably fitted to a back surface of the switch lever  2 , and a magnet  7  is held by the magnet lever  6 . The switch lever  2  assumes a rotational position shown in  FIG. 6   a  due to its own weight when the ice level in the ice storage chamber is lower than an installation height of the ice storage detection switch and no force is applied from the blocks of the ice to the switch lever  2 . In this case, the magnet  7  held by the magnet lever  6  is disposed in close vicinity of the reed switch  5 , which is ON.  
         [0006]     When the ice level in the ice storage chamber rises approximately up to the installation height of the ice storage detection switch as the production of the ice by the ice making portion progresses, the switch lever  2  is pressed by the blocks of the ice and its rotational position gradually shifts toward the switch case  1  as shown in  FIGS. 6   b  to  6   d . In accordance with the shift of the rotational position of the switch lever  2 , the magnet lever  6  comes into abutment with a corner portion of the reed switch holding portion  4  and rotates, so the magnet  7  held by the magnet lever  6  separates from the reed switch  5 . The reed switch  5  is turned OFF as a result of a change in a clearance between the reed switch  5  and the magnet  7  at this moment, and outputs an ice storage detection signal. Based on this ice storage detection signal, the operation of the ice making machine is stopped.  
         [0007]     In the conventional ice storage detection switch shown in  FIG. 6   a , however, the magnet lever  6  comes into abutment with the corner portion of the reed switch holding portion  4  to thereby rotate, the amount of change in the clearance between the reed switch  5  and the magnet  7  at the time when the switch lever  2  is pressed toward the switch case  1  is small. When variation of sensitivity exists across the reed switch  5 , there is a fear in that the ON/OFF operation may not be performed accurately. For instance, the operational reliability of the ice making machine deteriorates if the reed switch  5  is not turned OFF even when the switch lever  2  is pressed to the extent of coming into abutment with the switch case  1  as shown in  FIG. 6   d , or if the reed switch  5  is not turned ON even when the switch lever  2  has returned to its unpressed state as shown in  FIG. 6   a.    
       SUMMARY OF THE INVENTION  
       [0008]     The present invention has been made to eliminate such problems. Therefore, it is an object of the present invention to provide an ice storage detection switch capable of performing an ON/OFF operation accurately in accordance with an ice level.  
         [0009]     According to the present invention, there is provided an ice storage detection switch for detecting an ice level in an ice storage chamber of an ice making machine, the ice storage detection switch comprising: a switch case equipped with a reed switch and fixed in the ice storage chamber of the ice making machine; a switch lever having a magnet and movably fitted to the switch case; a magnet lever rotatably fitted to the switch lever, for holding a magnet so that the magnet is located in a vicinity of the reed switch when the switch lever is not pressed; and a projecting portion formed on the switch case to be located between a rotational center of the magnet lever and the reed switch, the ice level in the ice storage chamber being detected in accordance with a change in a clearance between the reed switch and the magnet, the magnet separating from the reed switch through abutment of the magnet lever on the projecting portion and rotation of the magnet lever when the switch lever is pressed by ice in the ice storage chamber. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view showing an ice making machine fitted with an ice storage detection switch according to a first embodiment of the present invention;  
         [0011]      FIGS. 2   a  to  2   d  are sectional views of the ice storage detection switch according to the first embodiment of the present invention showing successive stages of the operation at the time when a switch lever is pressed;  
         [0012]      FIG. 3  is a graph showing a change in a clearance between a reed switch and a magnet with respect to an operating distance of the switch lever;  
         [0013]      FIGS. 4   a  to  4   d  are sectional views of an ice storage detection switch according to a second embodiment of the present invention showing successive stages of the operation at the time when a switch lever is pressed;  
         [0014]      FIG. 5  is a perspective view showing a conventional ice storage detection switch; and  
         [0015]      FIGS. 6   a  to  6   d  are sectional views of the conventional ice storage detection switch showing successive stages of the operation at the time when a switch lever is pressed. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]     Embodiments of the present invention will be described hereinafter with reference to the accompanying drawings.  
         [0000]     First Embodiment  
         [0017]      FIG. 1  shows an ice making machine fitted with an ice storage detection switch according to the first embodiment of the present invention. An ice making portion  12  is disposed in an upper portion of an ice making machine body  11  in the shape of a rectangular parallelepiped, and an ice storage chamber  13  is formed below the ice making portion  12 . An opening/closing door  14  is provided in front of the ice storage chamber  13 , and the blocks of the ice in the ice storage chamber  13  can be taken out by opening the opening/closing door  14 . A machinery chamber  15  in which a compressor forming a refrigeration circuit and the like are accommodated is disposed below the ice storage chamber  13 .  
         [0018]     The blocks of the ice produced in the ice making portion  12  are sequentially stored in the ice storage chamber  13 . An ice storage detection switch  16  is fitted on an inner wall surface of the ice storage chamber  13 . When the ice level in the ice storage chamber  13  rises to reach the ice storage detection switch  16 , an ice storage detection signal is outputted from the ice storage detection switch  16  to stop an ice making operation.  
         [0019]     In the ice storage detection switch  16 , as shown in  FIG. 2   a , a switch lever  18  is fitted to a switch case  17  fixed to the inner wall surface of the ice storage chamber  13  so that the switch lever  18  can rotate about a rotational center  19 . A reed switch holding portion  20  is so formed on the switch case  17  as to protrude toward the switch lever  18 , and a reed switch  21  is embedded in the reed switch holding portion  20 . A magnet lever  22  is disposed on a back surface side of the switch lever  18 , that is, on the switch case  17  side. The magnet lever  22  is fitted at one end thereof to a rotational center  23  so as to be rotatable thereabout, and holds at the other end thereof a magnet  24 . Furthermore, a rib  25  as a projecting portion of the present invention is protrusively formed on the switch case  17  between the reed switch holding portion  20  and the rotational center  23  of the magnet lever  22  of the switch lever  18 .  
         [0020]     Next, an operation of the ice storage detection switch  16  according to the first embodiment of the present invention will be described. When the ice level in the ice storage chamber  13  is lower than an installation height of the ice storage detection switch  16  and no external force is applied horizontally from the blocks of the ice to the switch lever  18 , the switch lever  18  assumes a rotational position shown in  FIG. 2   a  due to its own weight. At this moment, the other end of the magnet lever  22  abuts on the reed switch holding portion  20  of the switch case  17 , and the magnet  24  held by the magnet lever  22  is disposed in the close vicinity of the reed switch  21 , which is ON. At this moment, the magnet lever  22  does not abut on a tip portion of the rib  25 , and there is formed a clearance between the magnet lever  22  and the rib  25 .  
         [0021]     When the ice level in the ice storage chamber  13  rises up to the installation height of the ice storage detection switch  16  as the production of the ice by the ice making portion  12  progresses, the switch lever  18  is pressed by the blocks of the ice to start rotating about the rotational center  19  toward the switch case  17  side. At this moment, the magnet lever  22  is rotatably fitted at one end thereof to the switch lever  18 , so the switch lever  18  rotates while the other end of the magnet lever  22  remains in abutment with the reed switch holding portion  20  of the switch case  17 . However, after a middle portion of the magnet lever  22  has come into abutment with the tip portion of the rib  25  as shown in  FIG. 2   b , the other end of the magnet lever  22  separates from the reed switch holding portion  20  as shown in  FIG. 2   c , and the switch lever  18  rotates while the middle portion of the magnet lever  22  remains in abutment with the tip portion of the rib  25 .  
         [0022]     As described above, one end of the magnet lever  22  moves toward the switch case  17  side together with the switch lever  18  while the middle portion of the magnet lever  22  remains in abutment with the tip portion of the rib  25 , so the magnet  24  held at the other end of the magnet lever  22  quickly separates from the reed switch  21 . Then, the switch  18  finishes its rotational operation when an end  18   a  of the switch lever  18  abuts on an inner surface of the switch case  17  as shown in  FIG. 2   d . At this moment, the clearance between the reed switch  21  and the magnet  24  becomes maximum.  
         [0023]     Due to a change in the clearance between the reed switch  21  and the magnet  24  resulting from the rotational operation of the switch lever  18 , the reed switch  21  is turned OFF and outputs an ice storage detection signal. Based on this ice storage detection signal, ice making operation of the ice making machine is stopped. After that, when the ice level in the ice storage chamber  13  lowers and the ice storage detection signal from the reed switch  21  is canceled by opening the opening/closing door  14  and consuming the blocks of the ice in the ice storage chamber  13 , ice making operation starts again.  
         [0024]     Here, the distance from the inner surface of the switch case  17  to the end  18   a  of the switch lever  18  is defined as an operating distance of the switch lever  18 .  FIG. 3  shows a result obtained by measuring changes in the clearance between the reed switch  21  and the magnet  24  with respect to the operating distance. For comparison, a measurement result of the ice storage detection switch of the conventional structure is also indicated by a broken line. In the ice storage detection switch  16  according to the first embodiment of the present invention, it is apparent that the clearance between the reed switch  21  and the magnet  24  quickly increases after the switch lever  18  has started rotating and, as shown in  FIG. 2   b , passed a point A where the middle portion of the magnet lever  22  abuts on the tip portion of the rib  25 .  
         [0025]     Thus, the operation of turning the reed switch  21  ON/OFF is reliably performed in accordance with the rotational operation of the switch lever  18  even when the variation of sensitivity exists across the reed switch  21 . That is, the reed switch  21  is reliably turned ON when the switch lever  18  is not pressed as shown in  FIG. 2   a , and the reed switch  21  is reliably turned OFF when the end  18   a  of the switch lever  18  is pressed to the extent of abutting on the inner surface of the switch case  17 . As a result, the operational reliability of the ice making machine is enhanced.  
         [0000]     Second Embodiment  
         [0026]      FIG. 4   a  shows an ice storage detection switch according to the second embodiment of the present invention. This ice storage detection switch is composed of, instead of the switch case  17  of the ice storage detection switch  16  according to the first embodiment shown in  FIG. 2 , a switch case  27  fixed to a lateral wall of the ice storage chamber  13  in such a manner as to be inclined toward an interior thereof, and is substantially identical in other structural details to the ice storage detection switch  16  of the first embodiment of the present invention. That is, the switch lever  18  is fitted to the switch case  27  so as to be rotatable about the rotational center  19 , and a reed switch holding portion  28 , in which the reed switch  21  is embedded, is so formed on the switch case  27  as to protrude toward the switch lever  18 . The magnet lever  22 , which is fitted at one end thereof to the rotational center  23  so as to be rotatable thereabout and holds at the other end thereof the magnet  24 , is disposed on the back surface side of the switch lever  18 . In addition, a projecting portion  29  is protrusively formed on the switch case  27  between the reed switch holding portion  28  and the rotational center  23  of the magnet lever  22  of the switch lever  18 .  
         [0027]     As shown in  FIG. 4   a , the inclination angle of the forward-inclined switch case  27  is set such that a lower end of the switch lever  18  separates from the switch case  27  due to its own weight when the switch lever  18  is not pressed by any block of ice. At this moment, the other end of the magnet lever  22  abuts on the reed switch holding portion  28  of the switch case  27 , and the magnet  24  held by the magnet lever  22  is disposed in the close vicinity of the reed switch  21 , which is ON.  
         [0028]     When the ice level in the ice storage chamber  13  rises as the production of the ice by the ice making portion  12  progresses and the switch lever  18  is pressed by the blocks of the ice, the switch lever  18  starts its rotational operation about the rotational center  19  toward the switch case  27  side. After the middle portion of the magnet lever  22  has come into abutment with the projecting portion  29  of the switch case  27  as shown in  FIG. 4   b , the other end of the magnet lever  22  separates from the reed switch holding portion  28  as shown in  FIG. 4   c , so the reed switch  21  is turned OFF.  
         [0029]     Since one end of the magnet lever  22  moves toward the switch case  27  side together with the switch lever  18  while the middle portion of the magnet lever  22  abuts on the projecting portion  29 , the magnet  24  held by the other end of the magnet lever  22  quickly separates from the reed switch  21 . When the end  18   a  of the switch lever  18  abuts on an inner surface of the switch case  27  as shown in  FIG. 4   d , the switch lever  18  finishes its rotational operation.  
         [0030]     As is the case with the first embodiment of the present invention, the ice making operation of the ice making machine is performed/stopped when the reed switch  21  is ON/OFF, respectively.  
         [0031]     According to the ice storage detection switch of the second embodiment of the present invention, the force required for pressing the switch lever  18  toward the switch case  27  side is only for the own weight of the switch lever  18 , so the ice level can be reliably detected even when the weight of the blocks of the ice is light.  
         [0032]     As described above, according to the present invention, the projecting portion is formed between the rotational center of the magnet lever and the reed switch, and the magnet lever abuts on the projecting portion to rotate when the switch lever is pressed, thereby allowing the magnet to separate from the reed switch. Therefore, the clearance between the reed switch and the magnet is increased, thereby making it possible to perform the ON/OFF operation accurately in accordance with the ice level.