Patent Publication Number: US-5894258-A

Title: Structure of combination type fusible plugs

Description:
BACKGROUND OF THE INVENTION 
     A fusible plug can provide safety in use. When current exceeds a specified value, the fuse will melt away so that current will be interrupted, preventing the occurrence of accidents. A prior fusible plug typically contains a shell, a plug seat, and a plurality of partitions in the shell for accommodating conductor copper blades, fuses, and conductor wires and terminals. Such structures are known in U.S. Pat. No. 5,281,943 and 5,482,478. Because that the interior of those prior fusible plug structures is still communicable, it is possible to have shorting between those conductor components when moisture infiltration, resulting in injury to human or damage to properties. Hence, a prior fusible plug has the concerns with safety. 
     In view of the above problem, the primary object of the invention is to provide an improved structure of combination type fusible plugs that comprises two independent plug seats each having a set of electrical wires, fuses, and conductor copper blades and jointly seated inside a shell. Thus the structure according to the invention can effectively eliminate the shortcoming of prior plugs. Now the structure and features of a fusible plug of the invention will be described in more detail with reference to accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS 
     FIG. 1 is a perspective view depicting the outer appearance of a fusible plug according to the invention. 
     FIG. 2 is an exploded view of the fusible plug of FIG. 1. 
     FIG. 3 shows another embodiment of a fusible plug according to the invention. 
     FIG. 4 is an exploded view of the plug of FIG. 3. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As shown in FIGS. 1 and 2, the plug of the invention mainly includes a shell (1), and two symmetrical plug seats (2, 3). The interiors of the plug seats (2, 3) are provided with partitions to for compartments for receiving conductor copper blades (21, 31) and fuses and electrical wires. The placement of those components is known to the public and so it will not be detailed here. The two sets of plug seats can be jointly incorporated into the shell (1), with a central partition (11) separating them from each other. 
     With such a configuration, the conductor copper blades, fuses and electrical wires in one plug seat are double protected from contact with parts in the other plug seat. Thus electrical shorting or leakage would never happen even if moisture infiltrates into the plug or there exists water vapor in the plug. 
     As shown in FIGS. 3 and 4, another embodiment of plug structure of the invention similarly contains a shell (1) and two symmetrical plug seats (2, 3). The plug seat is featured by a disk-like back plate (4) situated behind two plug seats. The back plate (4) is provided with a long slot (41) aiming at the gap between two plug seats (2, 3). When the back plate along with fuses and copper blades is put into the shell (1), a partition integrated with the shell will extend between two sets of plug seats and engage at the end thereof with the long slot (41). Therefore, the plug structure can also obtain the best protection, preventing electrical leakage and shorting as well as providing convenience in assembling. As a result, the plug structure according to the invention can eliminate the defects of a prior electrical plug and enhance the performance of a fusible plug.