Abstract:
A switching assembly of a gas stove includes a regulating valve, a knob, a stop board, and a restricting device. The regulating valve has a valve member and a regulating member, which is rotatable to regulate a gas flow through the valve member. The knob is connected to an end of a shaft which is connected to the regulating member with an opposite end thereof, and therefore the regulating member can be rotated by turning the knob. The stop board is located between the valve member and the knob, wherein the stop board has a curved slot, which has a first stop portion and a second stop portion. The restricting member is movable in the curved slot and is restricted by the first or the second stop portions. When the restricting member touches the first stop portion, the switching assembly allows larger gas flow to flow through.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates generally to a gas stove, and more particularly to a switching assembly of a gas stove. 
     2. Description of Related Art 
     Typically, conventional gas stoves are classified into natural gas type and gas cylinder type. The main difference between these types is the size of the gas passageway of the gas switch. The gas passageway of the natural gas type usually is larger than that of the liquid gas cylinder type. If a gas switch for natural gas type is mounted in a gas cylinder type gas stove, it will cause incomplete combustion because of the high gas supply. On the contrary, when a gas switch for gas cylinder type is mounted in a natural gas type gas stove, the stove only provides small flames because of the low gas supply. As a result, the manufacturers have to prepare both types of the gas switches for different gas stoves. It makes the cost higher. It will be good for the manufacturers of gas stove if there is a gas switch available for both types of the gas stoves. 
     BRIEF SUMMARY OF THE INVENTION 
     In view of the above, the primary objective of the present invention is to provide a switch assembly of a gas stove, which is available for both types of the gas stoves. 
     The present invention provides a switching assembly of a gas stove, which includes a regulating valve, a shaft, a knob, a stop board, and a restricting device. The regulating valve has a valve member and a regulating member, wherein the regulating member is received in the valve member, and rotatable to regulate a gas flow through the valve member. The shaft has an end connected to the regulating member. The knob is connected to an opposite end of the shaft to be turned to rotate the regulating member. The stop board is located between the valve member of the regulating valve and the knob, wherein the stop has a curved slot, which has a first stop portion, a second stop portion, and a third stop portion. The restricting device is connected to the knob and engaged in the curved slot of the stop board, wherein the restricting device is movable in the curved slot either between the second stop portion and the third stop portion, or between the first stop portion and the third stop portion. The knob is turnable within a first internal if the restricting device is movable between the second stop portion and the third stop portion, and is turnable within a second internal if the restricting device is movable between the first stop portion and the third stop portion, wherein when the knob is turnable within the second interval, a maximum gas flow which the regulating valve is able to supply is larger than that when the knob is turnable within the first interval. 
     With the design of above, the open area of the exit of the switching assembly is changeable, and therefore the open area of the switching assembly is both suitable for the gas stove of liquid gas cylinder or natural gas. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The present invention will be best understood by referring to the following detailed description of some illustrative embodiments in conjunction with the accompanying drawings, in which 
         FIG. 1  is a perspective view of a preferred embodiment of the present invention; 
         FIG. 2  is an exploded view of the first preferred embodiment of the present invention; 
         FIG. 3  is a sectional view of the  3 - 3  line in  FIG. 1 ; 
         FIG. 4  is a perspective view of the regulating member of the first preferred embodiment of the present invention; 
         FIG. 5  is a front view of the stop board of the first preferred embodiment of the present invention, showing the second post at the third stop portion; 
         FIG. 6  is a sectional view along the A-A line in  FIG. 1 , showing the position of the regulating member when the knob is turned to the position of  FIG. 5 ; 
         FIG. 7  is a front view of the stop board of the first preferred embodiment of the present invention, showing the second post at the first stop portion; 
         FIG. 8  is a sectional view along the A-A line in  FIG. 1 , showing the position of the regulating member when the knob is turned to the position of  FIG. 7 ; 
         FIG. 9  is a sketch diagram of the surface of the regulating when the knob is turned to the position of  FIG. 7 ; 
         FIG. 10  is a front view of the stop board of the first preferred embodiment of the present invention, showing the second post at the first stop portion; 
         FIG. 11  is a sectional view along the A-A line in  FIG. 1 , showing the position of the regulating member when the knob is turned to the position of  FIG. 10 ; 
         FIG. 12  is a sketch diagram of the surface of the regulating when the knob is turned to the position of  FIG. 10 ; 
         FIG. 13  is a perspective view of the knob of a second preferred embodiment of the present invention; and 
         FIG. 14  is a front view of the stop board of a third preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIGS. from  FIG. 1  to  FIG. 3 , a switching assembly of a gas stove of the first preferred embodiment of the present invention includes a regulating valve  10 , a knob  20 , a stop board  26 , and a restricting device  28 . 
     The regulating valve  10  includes a valve member  12 , a regulating member  16 , and a shaft  18 . The valve member  12  has a base  122  and a rear lid  124 . The base  122  has an input passageway  122   a , an output passageway  122   c , and a chamber  122   d . Gas enters the base  122  via the input passageway  122   a , and then flow to the chamber  122   d  and the output passageway  122   c  in sequence to leave the base  122  via the output passageway  122   c . An exit  122   b  is formed in the base  122  between the input passageway  122   a  and the chamber  122   c . The rear lid  124  is connected to a back side of the base  122 . 
     The regulating member  16  is received in the chamber  122   d  of the base  122  for rotation. As shown in  FIG. 3 , the regulating member  16  has an axial hole  162  along an axis of rotation, a first bore  163  and a second bore  164  respectively extending to the axial hole  162  in a direction perpendicular to the axis of rotation, and a guiding slot  166  on a surface  167  of the regulating member  16 . The axial hole  162  has an open end  162   a  and a closed end  162   b , and the open end  162   a  of the axial hole  162  is communicated with the output passageway  122   c  of the base  122 . The first bore  163  is larger than the second bore  164 . The second bore  164  extends to a bottom of a round slot  165  on the surface  167  of the regulating member  16 . The guiding slot  166  has a first end  166   a  and a second end  166   b  at opposite ends, wherein the first end  166   a  extends to the first bore  163 , and the second end  166   b  extends to the slot  165 . A width of the guiding slot  166  gradually narrows from to first end  166   a  to the second end  166   b . The first bore  163 , the second bore  164 , and the guiding slot  166  are aligned with the exit  122   b  of the input passageway  122   a  respectively when the regulating member  16  is being turned. With a change of the width of the guiding slot  166  when the he regulating member  16  is being turned, a gas flow through the regulating valve  10  is regulated. 
     The shaft  18  has an end inserted into a bore  124   a  on the rear lid  124  and is secured to the regulating member  16  by a pin  182 . The shaft  18  is turned to rotate the regulating member  16 . The knob  20  has a disk-like main member  22 , and the main member  22  has an outer side  222  and an inner side  226 . The main member  22  has a protrusion  224  on the outer side  222  to be held by user, and a post  23  and a tube  24  on the inner side  226 . The post  23  is provided with a bore  232  to engage the other end of the shaft  18 . 
     The stop board  26  is between the knob  20  and the valve member  12 , and has a through hole  262  and a hollow portion. In the present invention, the hollow portion is a curved slot  264  having a first stop portion  264   a , a second stop portion  264   b , and a third stop portion  264   c , wherein the first and the third stop portions  264   a ,  264   c  are at opposite ends of the curved slot  264 , and the second stop portion  264   b  is between the first and the third stop portions  264   a ,  264   c . A width of the curved slot  264  between the third and the second stop portions  264   c ,  264   b  is wider than that between the second and the first stop portions  264   b ,  264   a . In other words, the stop board  26  has a protrusion  264   d  between the second and the first stop portions  264   b ,  264   a , and the second stop portion  264   b  is formed on an end of the stop flange  264   d . The shaft  18  passes through the through hole  262 . 
     The restricting device  28  includes a first post  282  and a second post  284  on the inner side  226  of the main member  22  of the knob  20 . The second post  284  is beside the tube  24 , and is inserted into the curved slot  264 . In a particular circumference the first post  282  is taken off from the main member  22  and inserted into the tube  24  to be received in the curved slot  264  between the third and the second stop portions  264   c ,  264   b.    
     As shown in FIGS. form  FIG. 5  to  FIG. 8 , in a circumstance of the first post  282  not in the tube  24 , the knob  20  is able to rotate about 270 degrees while the second post  284  moves between the first and the third stop portions  264   a ,  264   c  ( FIG. 5  and  FIG. 7 ). When the second post  284  touches the third stop portion  264   c  ( FIG. 5 ), none of the guiding slot  166 , the first bore  163  and the second bore  164  is communicated with the input passageway  122   a  ( FIG. 6 ), so that no gas flows through the regulating valve  10 . In other words, the regulating valve  10  is turned off. It defines that a third open area is formed when the second post  284  touches the first stop portion  264   a . In the present embodiment, the third open area is zero. In another embodiment, the third open area is greater than zero by changing the locations of the third stop portion  264   c.    
     When the knob  20  is turned clockwise, the second post  284  moves from the third stop portion  264   c  toward the first stop portion  264   a , the guiding slot  166  is moved to a position under the input passageway  122   a , and the regulating valve  10  starts to supply a gas flow. The gas flow increases as the knob  20  is being turned, and when the second post  284  arrives at the first stop portion  264   a  ( FIG. 7 ), the first bore  163  is aligned with the input passageway  122   a , and the regulating valve  10  supplies a maximum gas flow. It defines that a first open area A 1  is formed when the second post  284  touches the first stop portion  264   a  ( FIG. 9 ). 
     As shown in  FIG. 10 , when the first post  282  is inserted into the tube  24 , the knob  20  is only able to rotate about 90 degrees while the first post  282  moves between the third and the second stop portions  264   c ,  264   b . When the second post  284  arrives at the second stop portion  264   b , a portion of the guiding slot  166  is aligned with the input passageway  122   a  ( FIG. 11  and  FIG. 12 ). It defines that a second open area A 2  is formed when the second post  284  touches the first stop portion  264   a  ( FIG. 9 ), and the first open area A 1  is greater than the second open area A 2 . 
     In conclusion, the knob  20  is turnable either within a first interval (the first post  282  moves between the third and the second stop portions  264   c ,  264   b ) or within a second interval (the second post  284  moves between the third and the first stop portions  264   c ,  264   a ), wherein the first interval and the second interval can be decided by whether the first post  282  is inserted into the tube  24  or not. In more details, when the first post  282  is inserted into the tube  24 , the knob  20  is turnable within the first interval to supply a small gas supply, which is suitable for the gas stove of liquid gas cylinder. On the contrary, when the knob  20  is turnable within the second interval, the regulating valve  10  supplies a large gas supply, which is suitable for the gas stove of natural gas. In the first interval, the first post  282  moves in a first path between the third and the second stop portions  264   c ,  264   b , and in the second interval, the second post  284  moves in a second path between the third and the first stop portions  264   c ,  264   a . Both the first and the second paths are in the curved slot  264 . The first path is parallel to the second path, and shorter than the second path. 
       FIG. 13  shows a knob  30  of the second preferred embodiment, which has a main member  32 , a first tube  322 , a second tube  324 , and a post  34 . The post  324  is inherently connected to the main member  32  when the main member  32  was made, and is taken off from the main member  32  to be inserted into the first tube  322  or into the second tube  324 . The same as above, the knob  30  is turnable either within a first interval or a second interval, which is decided by whether the post  34  is inserted into the first tube  322  or the second tube  324 . In the first interval, the post  34  is in the first tube  322 , and moves between the second and the third stop portions  362   b ,  362   c  for the gas stove of liquid gas cylinder. When the post  34  is inserted into the second tube  324 , the knob  30  is turnable within the second interval, and the post  34  moves between the first and the third stop portions  362   a ,  362   c  for the gas stove of natural gas. 
       FIG. 14  shows a stop board  36  of the third preferred embodiment, which has a first top portion  362   a  and a third stop portion  362   c  at opposite ends. A protrusion  362   d  is projected from a sidewall of the curved slot  362  to form a second stop portion  362   b . In an embodiment, the stop board  36  is a part of a case of the gas stove. In other word, the curved slot  362  is directly provided on the case of the gas stove, and it achieves the same function. 
     It must be pointed out that the embodiments described above are only some preferred embodiments of the present invention. All equivalent structures which employ the concepts disclosed in this specification and the appended claims should fall within the scope of the present invention.