Abstract:
A safety electric switch in which a safety plate is insertable through a button into an actuating member to lock the actuating member to the button for enabling the actuating member to be moved with the button to switch on/off the electric circuit.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to electric switches and more particularly, to a safety electric switch. 
   2. Description of the Related Art 
   Conventionally electric power switches are operable between a first position to switch on the electric circuit and a second position to switch off the electric circuit. These electric power switches are not safe in use. During the maintenance work of an electric power switch after the circuit has been switched off, other people may switch on the electric power, thereby causing an accident. 
   SUMMARY OF THE INVENTION 
   The present invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to provide a safety power switch, which prevents triggering of the electric circuit accidentally when switched off the electric circuit during a maintenance work. According to one aspect of the present invention, a safety plate is provided and insertable through a button into an actuating member to lock the actuating member to the button for enabling the actuating member to be moved with the button to switch on/off the electric circuit. When removed the safety plate from the safety electric switch, the actuating member is unlocked from the button. When pressing the button at this time, the actuating member does no work, and the safety electric switch is constantly kept on the original “ON” or “OFF” mode. Further, a lamp bulb is installed in the actuating member to produce a visual indication signal when the safety electric switch is switched on. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view of a safety electric switch according to the present invention. 
       FIG. 2  is a schematic sectional view of the present invention, showing the safety plate removed from the actuating member and the button. 
       FIG. 3  is a schematic sectional view of the present invention, showing the safety plate fastened to the button and the actuating member. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1˜3 , a safety electric switch in accordance with the present invention is shown comprised of a button  10 , an actuating member  20 , a panel  16 , a movable contact holder  33 , a casing  30 , two spring members  23 , and a safety plate  15 . 
   The panel  16  has a center opening  17 , a plurality of first through holes  18 , and a plurality of second through holes  19 . 
   The button  10  has a center through hole  11 , an annular bottom open chamber  13 , a plurality of bottom coupling rods  12  suspending in the annular bottom open chamber  13  and respectively slidably coupled to the second through holes  19  of the panel  16 , and a peripheral slot  14 . 
   The actuating member  20  is mounted in the annular bottom open chamber  13  of the button  10 , having a holder base  21  inserted through the center opening  17  of the panel  10 , a lamp bulb  25  mounted in the holder base  21  and aimed at the center through hole  11  of the button  10 , a lampshade  26  covering the lamp bulb  25 , a plurality of bottom coupling rods  22  respectively coupled to the first through holes  18 , and two locating grooves  24  disposed at the periphery. 
   The casing  30  has a plurality of metal terminals  31  mounted on the inside and electrically connected to power supply, and two guide rails  32  bilaterally disposed on the inside. 
   The movable contact holder  33  has a plurality of metal contact plates  34  disposed at the bottom side, and two guide grooves  35  disposed at the two distal ends thereof and respectively coupled to the guide rails  32  inside the casing  30  to guide movement of the movable contact holder  33  along the guide rails  32 . 
   The spring members  23  are connected between respective lugs  210  at the holder base  21  of the actuating member  20  and the movable contact holder  33 . 
   The safety plate  15  is inserted through the peripheral slot  14  and positioned in the locating grooves  24  at the periphery of the actuating member  20 . 
   After insertion of the safety plate  15  through the peripheral slot  14  into the locating grooves  24  at the periphery of the actuating member  20  (see  FIG. 3 ), the actuating member  20  is locked to the button  10  for synchronous movement with the button  10 . When pressed the button  10  at this time, the actuating member  20  is lowered with the button  10  to bias the spring members  23  in one direction, thereby causing the metal contact holder  33  to move upwards along the guide rails  32  away from the metal terminals  31  in the casing  30 , and therefore the safety electric switch is switched off. On the contrary, when pulled the button  10  upwards, the actuating member  20  is moved with the button  10  to bias the spring members  23  in the other direction, thereby causing the metal contact holder  33  to move downwards along the guide rails  32  and to force the respective metal contact plates  34  into contact with the respective metal terminals  31 , and therefore the electric safety switch is switched on. 
   When removed the safety plate  15  from the safety electric switch after the safety electric switch has been switched off, the actuating member  20  is unlocked from the button  10  (see  FIG. 2 ). At this time, pressing the button  10  does not move the actuating member  20 , and the safety electric switch is constantly maintained in “Off” status. On the contrary, when removed the safety plate  15  from the safety electric switch after the safety electric switch has been switched on, the actuating member  20  is unlocked from the button  10  (see  FIG. 2 ). At this time, pressing the button  10  does not move the actuating member  20 , and the safety electric switch is constantly maintained in “ON” status. 
   Further, when the safety electric switch is switched on, the lamp bulb  25  is turned on to emit light. On the contrary, when the safety electric switch is switched off, the lamp bulb  25  is off too. 
   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.