Abstract:
An additional active safety switch for gas burner with active restoring capability is provided to actively prevent the ignition trigger of the gas burner from being pulled arbitrarily or from keeping enabled constantly for enhancement of security.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to a safety switch for a gas burner, and more particularly, it relates to an active safety switch for a gas burner that can restore actively to prevent the ignition trigger from being pulled arbitrarily or from keeping enabled constantly for enhancement of security. 
     Usually, a gas burner will continuously burns as long as it is kindled and switch is kept open. For snuffing the gas burner out, a user has to take an action to close the gas switch, or in the case where the gas switch is interacted with a trigger, the flame is extinguished automatically as soon as the trigger is released. However, under either case mentioned, the gas burner lacks an active safety switch for the prevention of accidental ignition or any unnecessary conflagration. 
     In using an existing gas burner, which is generally provided with an auxiliary closing mechanism, a user should not forget to have the auxiliary closing mechanism effectuated to disable the trigger and ensure safety when he puts out the gas burner, or a disaster beyond compensation might be incurred if the trigger is pulled by a child or somebody else who is ignorant to danger of the gas burner. 
     In view of abovesaid imperfections, after years of constant effort in research, the inventor of this invention has consequently developed and proposed an improved mechanism pertaining to the subject matter for prevention of unnecessary accidents in using a gas burner. 
     SUMMARY OF THE INVENTION 
     The primary object of this invention is to provide an active safety switch for gas burner that can restore actively to prevent the ignition trigger from being pulled arbitrarily or from keeping enabled constantly to ensure safety in using a gas burner. 
     For more detailed information regarding this invention together with further advantages or features thereof, at least an example of preferred embodiment will be elucidated below with reference to the annexed drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The related drawings in connection with the detailed description of this invention to be made later are described briefly as follows in which: 
     FIG. 1 is a three-dimensional schematic view of this invention; 
     FIG. 2 is a three-dimensional exploded view of this invention; 
     FIG. 3 is a cutaway sectional view taken along line III—III in FIG. 1; 
     FIG. 4A is an action diagram of an active safety switch of this invention; 
     FIG. 4B is another action diagram of the active safety switch of this invention; and 
     FIG. 4C is yet another action diagram of the active safety switch of this invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIG.  1  through FIG. 3, a gas burner  1  mainly comprises a handgrip  11 , a top strap  12  on the handgrip  11 , a valve  13  underneath the top strap  12 , a safety switch  14  at rear end of the top strap  12 , a positioning pin  16  penetratingly anchored in the top strap  12 , a trigger  15  disposed at a front lower end of the top strap  12 , and a piezoelectric element  17  located between the valve  13  and the handgrip  11 . 
     A gas tank  111  having a gas inlet pipe  112  is placed in the handgrip  11 . 
     A switch slide channel  121  formed at one end of the top strap  12  is provided with a protrusion block  122  situated at inner upper edge of the switch slide channel  121 , and a positioning hole  123  is perforated at both lateral faces of the stop strap  12 , and further, an adjustment slot  124  is reserved at rear end of the top strap  12 . 
     The valve  13  is used to close, open, and adjust the gas flow, wherein a propping rod  131  for opening or closing gas flow is arranged at a lower end of the valve  13 ; an adjustment button  132  is disposed at tail end of the valve  13 ; and, the adjustment button  132  is sleeve-jointed with an adjustment knob  133  for adjusting flame of the gas burner  1 . 
     The safety switch  14  disposed in the switch slide channel  121  of the top strap  12  comprises a driving block  141  and a pressing block  143  secured to the driving block  141 , wherein a protrusion rod  144  on the pressing block  143  penetrates through and slightly projects over a through hole  142  of the driving block  141 ; an extension arm  146  having a protrusion rod  147  protrusively situated at its one end face and sleeve-jointed with a resilient body  149  is disposed at an end face of the driving block  141 ; a stop portion  145  is extended along both lateral faces of the pressing block  143  to seemingly prop the protrusion block  122  of the top strap  12 ; and, a stop block  148  is protrusively arranged on a lateral face of the pressing block  143 . 
     Moreover, the lower end of the trigger  15  is a pressing portion  151 , wherein a positioning groove  155  is formed at a lateral face of top edge of the pressing portion  151  and the other lateral face is a prop-and-tug portion  152 ; the top edge of the prop-and-tug portion  152  is extended to form an extension piece  153  whose tail end seemingly props the stop block  148  of the safety switch  14 ; and, a wedged groove  154  is formed in top face of the extension piece  153 . 
     The positioning pin  16  is penetratingly disposed in the positioning hole  123  of the top strap  12  and is transversely laid on the pressing portion  151  of the trigger  15 , and besides, a first and a second pressing head  161 ,  162  are placed at two ends of the positioning pin  16  respectively. 
     The piezoelectric element  17  used for creating sparks is a switch with an extended ignition line  171 , and a start portion  172  of the piezoelectric element  17  is in contact with the prop-and-tug portion  152  of the trigger  15 . 
     For keeping the gas burner  1  under flame-spouting state, a user is supposed to poke the positioning pin  16  to another side, and at this moment, the first pressing head  161  at one end of the positioning pin  16  is inserted in the positioning groove  155  for positioning the trigger  15  to allow continuous supply of the gas. When the second pressing head  162  is pressed, the first pressing head  161  will detach from the positioning groove  155  of the trigger  15  to shut down the gas supply. 
     Referring to FIG.  4 A through FIG. 4C, when the protrusion rod  144  of the safety switch  14  is pressed, the stop portion  145  which normally props the protrusion block  122  of the top strap  12  will be separated to push the driving block  141  of the safety switch  14  upwards. At this moment, the trigger  15  which normally props the stop block  148  of the pressing block  143  will move sideward, and the prop-and-tug portion  152  is supposed to push the piezoelectric element  17  to start and create sparks at a sparking end  173  of the ignition line  171 . Meanwhile, the propping rod  131  of the valve  13  entrapped in the wedged groove  154  of the extension piece  153  is to be propped up to release the gas in the gas tank  111  via the gas inlet pipe  112  for being kindled by the created sparks. 
     In short, as a safety switch is available, the trigger of the gas burner cannot be pulled arbitrarily, and because it can be restored actively, any accidental pull of the trigger is prevented. Besides, a positioning pin of this invention is controllable for continuous supply of the gas without needing pulling the trigger continuously. 
     Although, this invention has been described in terms of preferred embodiments, it is apparent that numerous variations and modifications may be made without departing from the true spirit and scope thereof, as set forth in the following claims.