Abstract:
An apparatus for diagnosing a tripped fuse is disclosed. The apparatus employs a chemical light installed at an upper portion of the fuse housing. A system for activating the chemical light is installed at the lower end of the housing. The activation system activates the light when an excessive current melts a soft iron element.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a fuse for vehicle circuits. More particularly, it relates to an apparatus for diagnosing the breaking of a fuse that confirms the fuse is broken by activating a chemical light.  
         BACKGROUND OF THE INVENTION  
         [0002]    The most recent developments in the electrical industry for convenience and safety are installed in the latest vehicles more frequently than ever before. This tendency has led to a corresponding increase in the use of fuses, which open to protect a circuit in case of an excessive current. It is, therefore, an important matter whether a fuse is tripped or not because it may control the function of one of the safety apparatuses.  
           [0003]    A tripped fuse is typically found by inspection. The typical fuse generally includes a pair of connecting terminals that are connected through electric wires to an electric power source terminal and a ground, respectively. The typical fuse also contains a soft iron element that connects the pair of connecting terminals to each other. The soft iron element melts when an excessive current flows through it and isolates the pair of connecting terminals from each other. A pair of conductive terminals on the outside of the typical fuse are used for confirming whether the soft iron element is broken.  
           [0004]    When checking whether the fuse is tripped, a dedicated tester may be used. The melting of the soft iron element is confirmed by checking whether there is connectivity between the pair of conductive terminals. But it is difficult to check the state of the fuse using the naked eye and dedicated testers are rare. Thus, time is taken unnecessarily because a general tester must be used.  
         SUMMARY OF THE INVENTION  
         [0005]    A preferred embodiment of the present invention includes a pair of connecting terminals that are connected through electric wires with an electric power source terminal and a ground, respectively, a soft iron element that connects the pair of connecting terminals with each other, the soft iron element melting the pair of connecting terminals from each other when an excessive current flows through the soft iron element, and a pair of conductive terminals that are used for confirming whether the connecting terminals are isolated from each other from outside the apparatus. A chemical light is installed in an upper portion of a housing of the fuse. An activation system for activating the chemical light  14  to radiate is installed at a lower end of the housing. Chemical mixtures react when the activation system is operated by the melting of the soft iron element, thereby radiating light.  
           [0006]    In a preferred embodiment of the invention, an apparatus for diagnosing a tripped fuse, comprises a light visible on the surface of a fuse; and an activation system comprising an elastic element, wherein the activation system activates the light when the fuse is tripped. In a preferred embodiment the light is a chemical light and comprises: an oxalate; and an activator that when mixed with the oxalate creates light, wherein the activator and the oxalate are caused to mix by an action of the elastic element. Also, a preferred embodiment comprises a glass tube containing the actuator; and a housing containing the oxalate, wherein the glass tube and housing are dimensioned and configured so that if the glass tube broke the activator would mix with the oxalate, and wherein the action of the elastic element is to exert force against the glass tube to break the glass tube. A further preferred embodiment comprises a soft iron element, wherein the soft iron element restrains the elastic element and prevents the elastic element from returning to a first position, and wherein the activating system activates the light by allowing the elastic element to move toward the first position. Additional, a preferred embodiment comprises a wire connecting the elastic element to the soft iron element and wherein the activation system allows the elastic element to move toward the first position in response to an excessive current flowing through and melting the soft iron element. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    The above objects and other characteristics and advantages of the present invention will become more apparent in the following detailed description of a preferred embodiment, with reference to the attached drawings, in which:  
         [0008]    [0008]FIG. 1 is a sectional view of a fuse and an apparatus for diagnosing the fuse according to a preferred embodiment of the present invention; and  
         [0009]    [0009]FIG. 2 is a view illustrating an operation state of the apparatus of FIG. 1.  
         [0010]    Like numbers refer to similar elements throughout the several drawings. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]    A preferred embodiment of the present invention, as shown in FIG. 1, includes a chemical light  14  that is received in an upper portion of a housing of a fuse  10 , and an activation system for causing the chemical light  14  to radiate light. The activation system is installed at the lower end of the housing and connects to the fuse  10 . The fuse  10  includes a pair of connecting terminals  11   a  and  11   b  that are connected through electric wires to an electric power source terminal and a ground, respectively. A soft iron element  12  connects the connecting terminals  11  a and  11   b  with each other. A pair of conductive terminals  13   a  and  13   b  on the outside of fuse  10  are used for confirming whether the soft iron element  12  is broken.  
         [0012]    The activation system preferably includes a plate spring  15  for applying an elastic force to chemical light  14  that causes a glass tube  14   b  of the chemical light  14  to burst. A wire  16  causes the soft iron element  12  to maintain the plate spring  15  in a tensioned state  
         [0013]    The chemical light  14  is observable from the exterior of the fuse  10 . Glass tube  14   b  contains an activator. The activator may be a chemical mixture having dimethyl phthalate (DMP), butanol, hydrogen peroxide, etc. A chemical mixture called the “oxalate”, having DBP, oxalic chloride, dye, etc., is included in the outer shell  14   a . Light radiating chemical compositions and reactions are not described in detail because the compositions and reactions are well known to those of ordinary skill in the art. But briefly, when the glass tube  14   b  is burst, the chemical mixture reacts with the oxalate so that a light is radiated.  
         [0014]    The plate spring  15  is attached to a part of the outer shell  14   a . The plate spring  15  is demarcated and pulled by the wire  16 . Thus, plate spring  15  creates an upward tension in wire  16 . The glass tube  14   b , which is installed in the outer shell  14   a , preferably has a shape of a curve and is attached to a middle portion of the plate spring  15 . Glass tube  14   b  is relatively fragile. Therefore, when soft iron element  12  melts and releases wire  16 , plate spring  15  elastically retracts against, and breaks, glass tube  14   b . This causes the activator to mix with the oxalate and radiate light.  
         [0015]    Furthermore, the plate spring  15  is preferably integrally formed on the outer shell  14   a . Though a space is generated when the middle portion of the plate spring  15  is pulled, the space is filled because the outer shell  14   a  is made of a flexible material.  
         [0016]    When the fuse  10  is not broken, the plate spring  15  is in tension with the wire  16  that is connected to the soft iron element  12 . When the fuse  10  is broken, the tension is removed. The elastic force of the plate spring  15  is transferred to the capillary glass tube  14   b , breaking the tube, and mixing the activator with the oxalate. Light is generated by the reaction of the activator and oxalate. A user confirms that the fuse is broken by observing a light on the surface of the fuse  10 .  
         [0017]    As described above, according to a preferred embodiment of the present invention, it is possible to easily and efficiently check the state of the fuse using the chemical light.  
         [0018]    While the present invention has been particularly shown and described with reference to a particular embodiment thereof, it will be understood by those skilled in the art that various changes in form and detail may be effected therein without departing from the spirit and scope of the invention as defined by the appended claims.