Cartridge thermal fuse with an adhesive metal excellent in adhesion with the melted fusible alloy

• US 5,631,621 A
• Filed: 12/22/1995
• Issued: 05/20/1997
• Est. Priority Date: 12/22/1994
• Status: Expired due to Fees

• Current Assignee: Takuo Nakajima
• Original Assignee: Takuo Nakajima
• Inventors: Nakajima, Takuo
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): Gandhi, Jayprakash N.
• Application Number:
  US08/577,220
• Time in Patent Office: 515 Days
• Field of Search: 337/201, 337/252, 337/227, 337/228, 337/268, 337/273, 337/279, 337/280
• US Class Current: 337/280
• CPC Class Codes: H01H 2037/768 characterised by the composition of the fusible material
• CPC Class Codes: H01H 37/761 with a fusible element forming part of the switched circuit H01H37/767 takes precedence

Abstract

The thermal fuse comprises a fuse base having a wire fuse element of a fusible alloy connecting lead wires and a cartridge forming an enclosed space for accommodating the wire fuse element by surrounding the wire fuse element and closing both ends thereof at the lead wires. In this space, a sucker having a suction surface composed of an adhesive metal excellent in adhesion with the fusible alloy is disposed.

Claims

1. A thermal fuse comprising

a fuse base composed of a wire fuse element made of a fusible alloy melted by heating and lead wires connected to both ends of the wire fuse element and

a cartridge extending between the lead wires in the lengthwise direction thereof, while surrounding the wire fuse element, and of which both ends being fixed and closed at the lead wires so as to form an enclosed space for accommodating the wire fuse element, wherein

the cartridge and lead wires are insulated, and

a sucker having a suction surface composed of an adhesive metal excellent in adhesion with the melted fusible alloy is disposed in the space, while facing the suction surface to the wire fuse element.

2. The thermal fuse of claim 1, wherein said sucker is a disk having the suction surface formed on the side surface disposed in contact with or closely to the end surface of the wire fuse element.

3. The thermal fuse of claim 1, wherein said sucker is a cup having the suction surfaces formed on the circumferential surface surrounding the wire fuse element and on the bottom closing the circumferential surface in contact with or closely to the end surface of the wire fuse element.

4. The thermal fuse of claim 1, wherein said sucker is an external ring having a length L1 of not more than 0.5 times the length L0 of the wire fuse element to be externally fitted to the wire fuse element, and having the suction surface formed on the surface.

5. The thermal fuse of claim 4, wherein said external ring is a disk having a central hole in which the wire fuse element is fitted.

6. The thermal fuse of claim 4, wherein said external ring has the central hole formed in a polygonal shape so as to contact with the wire fuse element at two or more points.

7. The thermal fuse of claim 4, wherein said external ring has a division line extending continuously from one end to the other end so that the inside diameter of the external ring may be variable.

8. The thermal fuse of claim 7, wherein said external ring is a spiral coil of adhesive metal wire material, and the adjacent wire material sides form the division line.

9. The thermal fuse of claim 7, wherein said external ring is a cylindrically wound tubular form of an adhesive metal hoop material, and the winding start end and winding terminal end of the hoop material form the division line.