Electronic devices having reduced destruction of internal elements upon malfunction

Abstract

A positive thermistor device includes a positive thermistor element having a pair of opposed electrodes, each of which receives compressive force elastically applied from a corresponding one of spring contact members to hold the thermistor element at a predefined position in the device. When the thermistor device is destroyed, the element breaks into fragments, some of which remain in contact with the spring contact members. The remaining fragments deviate in position to ensure that they do not conduct electricity, resulting in an open state, wherein any current flow is inhibited through such fragments. More specifically, a positive thermistor disk is held within the device so that it is interposed between conductive spring contact pieces and insulative position-alignment projections, which are cross-diagonally situated with respect to each other. The spring contact pieces are located further toward the periphery of the disk than the position-alignment projections, causing a spring force to extend in a direction generally outward relative to a direction perpendicular to the planes of the electrodes. In one embodiment, the position-alignment projections have cut-away portions at outer tip ends thereof respectively to further promote the formation of an open circuit state upon the occurrence of malfunction.

What is claimed is:  
     
         1 . An electronic device comprising: 
 an electronic element having first and second opposed electrodes;    support means for elastically supporting said electronic element, said support means including first and second contact sections in contact with said first electrode at different positions thereon, and third and fourth contact sections in contact with said second electrode at different positions thereon;    the first and fourth contact sections being located closer to outer peripheral portions of said first and second electrodes than the third and second contact sections;    said first and fourth contact sections being electrically connected with said first and second electrodes respectively to provide a conductive path for application of power to said electronic element; and    the second and third contact sections being electrically isolated from said first and second electrodes.    
     
     
         2 . The device according to    claim 1   , wherein said support means comprises: 
 a first conductive terminal member having first and second spring contact pieces for elastically applying compressive force toward said first electrode;    a second conductive terminal member having third and fourth spring contact pieces for elastically applying compressive force toward said second electrode;    a first insulative member between said second spring contact piece and said first electrode;    a second insulative member between said third spring contact piece and said second electrode; and    said first spring contact piece, said first insulative member, said second insulative member and said fourth spring contact piece constituting said first, second, third and fourth contact sections respectively.    
     
     
         3 . The device according to    claim 1   , wherein said support means comprises: 
 a first conductive terminal member having a first spring contact piece for elastically applying compressive force toward said first electrode;    a first insulative member in contact with said first electrode;    a second insulative member contacted with said second electrode;    a second conductive terminal member having a second spring contact piece for elastically applying compressive force toward said second electrode; and    said first spring contact piece, said first insulative member, said second insulative member and said second spring contact piece constituting said first, second, third and fourth contact sections, respectively.    
     
     
         4 . The device according to    claim 3   , further comprising a casing for holding therein said electronic element and said first and second terminal members, and wherein said first and second insulative members are associated with said casing.  
     
     
         5 . The device according to    claim 1   , wherein said electronic element is a positive thermistor.  
     
     
         6 . An electronic device comprising: 
 an electronic element having first and second principal planes on opposite sides thereof, respectively, and first and second electrodes formed on said first and second principal planes respectively;    a pair of a first conductive spring contact piece and a first insulative position-alignment projection being contacted with said first principal plane at different positions thereon;    a pair of a second conductive spring contact piece and a second insulative position-alignment projection being contacted with said second principal plane at different positions thereon;    said first and second spring contact pieces being elastically contacted with said first and second electrodes respectively while providing an electrical conductive state therebetween;    said first spring contact piece being located closer to an outer periphery of said electronic element than said second position-alignment projection while causing said first spring contact piece to oppose said second position alignment projection with said electronic element being interposed therebetween;    said second spring contact piece being located closer to an outer periphery of said electronic element than said first position-alignment projection while causing said second spring contact piece to oppose said first position alignment projection with said electronic element being interposed therebetween; and    each of said first and second spring contact pieces defining a spring force directed generally away from a direction which is perpendicular to said principal planes.    
     
     
         7 . An electronic device comprising: 
 an electronic element having first and second principal planes on opposite sides thereof, respectively, and first and second electrodes formed on said first and second principal planes respectively;    a pair of a first conductive spring contact piece and a first insulative position-alignment projection in contact with said first principal plane at different positions thereon;    a pair of a second conductive spring contact piece and a second insulative position-alignment projection in contact with said second principal plane at different positions thereon;    said first spring contact piece and said second spring contact pieces in elastic contact with said first and second electrodes respectively while providing electrical conductive state therebetween;    said first spring contact piece being located closer to an outer periphery of said electronic element than said second position-alignment projection, while causing said first spring contact piece to oppose said second position alignment projection with said electronic element being interposed therebetween;    said second spring contact piece being located closer to an outer periphery of said electronic element than said first position-alignment projection while causing said second spring contact piece to oppose said first position alignment projection with said electronic element being interposed therebetween; and    each of the first and second position-alignment projections having a tip end being partly cut away at its outer side facing the outer periphery of said electronic element.    
     
     
         8 . An electronic device comprising: 
 an electronic element having first and second principal planes on opposite sides thereof, respectively, and first and second electrodes formed on said first and second principal planes respectively;    a pair of a first conductive spring contact piece and a first insulative position-alignment projection in contact with said first principal plane at different positions thereon;    a pair of a second conductive spring contact piece and a second insulative position-alignment projection in contact with said second principal plane at different positions thereon;    said first spring contact piece and said second spring contact pieces in elastic contact with said first and second electrodes respectively while providing electrical conductive state therebetween;    said first spring contact piece being located closer to an outer periphery of said electronic element than said second position-alignment projection, while causing said first spring contact piece to oppose said second position alignment projection with said electronic element being interposed therebetween;    said second spring contact piece being located closer to an outer periphery of said electronic element than said first position-alignment projection while causing said second spring contact piece to oppose said first position alignment projection with said electronic element being interposed therebetween;    each of the first and second spring contact pieces defining a spring force directed generally outward relative to a direction perpendicular to said principal planes; and    each of the first and second position-alignment projections having a tip end being partly cut away at its outer side facing the outer periphery of said electronic element.    
     
     
         9 . The device according to    claim 6   , further comprising a casing for holding therein said electronic element and said first and second spring contact pieces, and wherein said first and second position alignment projections are associated with said casing.  
     
     
         10 . The device according to    claim 2   , wherein said electronic element is a positive thermistor.  
     
     
         11 . The device according to    claim 3   , wherein said electronic element is a positive thermistor.  
     
     
         12 . The device according to    claim 4   , wherein said electronic element is a positive thermistor.  
     
     
         13 . The device according to    claim 6   , wherein said electronic element is a positive thermistor.  
     
     
         14 . The device according to    claim 7   , wherein said electronic element is a positive thermistor.  
     
     
         15 . The device according to    claim 8   , wherein said electronic element is a positive thermistor.  
     
     
         16 . The device according to    claim 9   , wherein said electronic element is a positive thermistor.  
     
     
         17 . The device according to    claim 7   , further comprising a casing for holding therein said electronic element and said first and second spring contact pieces, and wherein said first and second position alignment projections are associated with said casing.  
     
     
         18 . The device according to    claim 8   , further comprising a casing for holding therein said electronic element and said first and second spring contact pieces, and wherein said first and second position alignment projections are associated with said casing.