Patent Publication Number: US-2011050439-A1

Title: Protector having a dual-warning outer casing

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a protector having a dual-warning outer casing. 
     2. Description of the Prior Art 
     Generally, there is a protector disposed between a telecommunication cable and a switchboard apparatus for preventing the equipment from being damaged because of a short circuit or a lightning strike. A conventional protector comprises a protection circuit and an alarm circuit. The protection circuit uses a thermistor and a semiconductor discharge tube for protecting it from over voltage or over current. The alarm circuit uses an illuminating member to activate a photoresistor which is adapted to start a light emitting diode to radiate light for providing a warning to remind the maintenance personnel of abnormal circuit. However, the conventional protector is unable to remind the maintenance personnel of high voltage when the parts in the protector have a breakdown or aging, which may cause an accident because of getting an electric shock. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve this problem. 
     SUMMARY OF THE INVENTION 
     A protector having a dual-warning outer casing includes a housing and a circuit board. The housing has one end formed with a pull portion. The pull portion has a through hole for insertion of an illuminating unit. The circuit board is disposed in the housing and includes two protection modules, a first alarm module and a second alarm module thereon. The first alarm module and the second alarm module are connected with the illuminating unit. Thereby, the protector is capable of sending warnings for abnormal circuit and high voltage via the illuminating unit, preventing the maintenance personnel from getting an electric shock. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view according to a first embodiment of the present invention; 
         FIG. 2  is a partially enlarged view according to the first embodiment of the present invention; 
         FIG. 3  is a schematic view showing the circuit of a circuit board of the present invention; and 
         FIG. 4  is a partially enlarged view according to a second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings. 
     As shown in  FIGS. 1 and 2 , a protector  100  according to a first embodiment of the present invention is disposed between a telecommunication cable and a switchboard apparatus, and comprises a housing  10 , a circuit board  20 , and an illuminating unit  30 . 
     The housing  10  has one end formed with a pull portion  11 . The pull portion  11  is made of transparent material and formed with a through hole  12 . 
     The circuit board  20  is disposed in the housing  10 , and comprises two protection modules  21 , a first alarm module  22  and a second alarm module  23  thereon. 
     The illuminating unit  30  is disposed in the pull portion  11  of the housing  10 . In this embodiment, the illuminating unit  30  comprises a first light emitting diode  31  disposed in the through hole  12  and two second light emitting diodes  32  disposed on the circuit board  20 . The first light emitting diode  31  is electrically connected to the first alarm module  22 , and the second light emitting diodes  32  are electrically connected to the second alarm module  23 . 
       FIG. 3  is a schematic view showing the circuit of the circuit board of the present invention. The circuit board  20  includes a aa′ signal line, a bb′ signal line, a ground wire E. Each of the aa′ signal line and the bb′ signal line is provided with the protection module  21 . The following description for the aa′ signal line provided with the protection module  21  is to give an example. The protection module  21  includes a thermistor  211  connected to the aa′ signal line in the way of series connection, a fuse  212  disposed in front of the thermistor  211 , a semiconductor discharge tube  213  connected between the aa′ signal line and the ground wire E, and a voltage dependent resistor  214  connected between the aa′ signal line and the ground wire E. 
     The first alarm module  22  includes a first resistor  221  and a third light emitting diode  222  which are connected to the aa′ signal line/bb′ signal line in the way of parallel connection, and a phototransistor  223  located at a rear end of the protection module  21  and connected to the ground wire E in the way of series connection. The phototransistor  223  is close to the third light emitting diode  222 , and has a rear end connected to the first light emitting diode  31  of the illuminating unit  30 . 
     The second alarm module  23  includes a second resistor  231  connected to the aa′ signal line/bb′ signal line in the way of parallel connection. The resistance valve of the second resistor  231  is much greater than that of the first resistor  221 . The second resistor  231  has a rear end connected to the second light emitting diode  32  of the illuminating unit  30 . 
     Referring to  FIGS. 2 and 3 , in this embodiment when there is a surge on the aa′ signal line, the semiconductor discharge tube  213  of the protection module  21  will from a closed circuit and guide most current to the ground wire E. In the meantime, the resistance valve of the thermistor  211  will rise quickly, and partial current will be forced to go through the first alarm module  22  for starting the third light emitting diode  222  to radiate light. When the phototransistor  223  is shone, the first light emitting diode  31  of the illuminating unit  30  will be trigged to radiate light for warning the maintenance personnel of abnormal circuit. Because the resistance valve of the second resistor  231  of the second alarm module  23  is much greater than those of the first resistor  221  and the thermistor  211 , only minimal current passes therethrough, which is unable to start the second light emitting diode  32  of the illuminating unit  30 . 
     The parts in the protector  100  may become aging. In this embodiment, the semiconductor discharge tube  23  on the aa′ signal line becoming aging is given as an example. When there is a surge, the semiconductor discharge tube  231  fails to form a closed circuit. Thus, the resistance valve of the thermistor  211  rises quickly to form high current, which will blow the fuse  212 . The current will be forced to go toward the first alarm module  22  and the second alarm module  23  for starting the first light emitting diode  31  and the second light emitting diode  32  to radiate light. The pull portion  11  of the housing  10  is made of transparent material such that the maintenance personnel is able to know that the protector  100  has high voltage when the second light emitting diodes  32  is radiating light, preventing the maintenance personnel from getting an electric shock. 
       FIG. 4  is a perspective view of a second embodiment of the present invention, which is substantially similar to the first embodiment with the exceptions described hereinafter. The illuminating unit  30  is a multi-core light emitting diode  33  disposed in the through hole  12  of the pull portion  11 . In this embodiment, the multi-core light emitting diode  33  has three cores  331 . The central one is connected to the first alarm module  22  to radiate orange light, and the sideway ones are connected to the second alarm module  23  to radiate red light. Thereby, the illuminating unit  30  uses different color light to warn the maintenance personnel of abnormal circuit and high voltage. 
     Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims.