Fuse for thick film device

• US 4,533,896 A
• Filed: 11/28/1983
• Issued: 08/06/1985
• Est. Priority Date: 11/28/1983
• Status: Expired due to Fees

• Current Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Belopolsky, Yakov
• Primary Examiner(s): Mayewsky, Volodymyr Y.
• Application Number:
  US06/555,339
• Time in Patent Office: 617 Days
• Field of Search: 219/212, 219/253, 219/512, 219/517, 219/528, 219/543, 338/309, 338/195, 338/305, 338/309, 338/314, 29/620, 337/142, 337/145, 337/160, 337/180, 337/187, 337/191, 337/229, 337/231, 337/232, 337/290, 337/292, 337/295, 337/401
• US Class Current: 337/232
• CPC Class Codes: H01H 2085/0275 Structural association with a printed circuit board
• CPC Class Codes: H01H 85/0411 Miniature fuses

Abstract

A fuse is disclosed for protecting thick film devices. The fuse comprises two blocks of material mounted to the substrate that carries the thick film device. The blocks are mounted in close proximity to one another, in axial alignment, but in a spaced apart relationship. An electrically conductive fusible link (e.g. solder) straddles the two blocks so as to complete an electric circuit.

Claims

1. A fuse, for mounting on an electrically insulative substrate to protect a thick film device mounted on said substrate and connected electrically in series with said fuse, said fuse characterized by:

two electrically conductive terminal block means, for electrical connection to electrodes carried by said substrate, said two block means in close proximity to one anther, in axial alignment, but in a spaced apart relationship; and

an electrically conductive fusible link means protruding into respective mating holes in each of said two terminal block means and electrically connected thereto so as to complete an electric circuit between said two block means whereby said mating holes are larger than necessary to accept said fusible link, so as to allow molten material from the fusible link to move into said mating holes due to capillary action when said fusible link melts due to excessive heat.

2. The fuse of claim 1 wherein said thick film device is a resistor.

3. The fuse of claim 2 wherein said fusible link is comprised of solder.

4. The fuse of claim 2 wherein said fusible link is a piece of flux-core solder.

5. The fuse of claim 3 wherein said two terminal block means are each rectangular parallelepipeds.

6. A fuse, for mounting on an electrically insulative substrate in order to protect a thick film resistor mounted on said substrate and connected electrically in series with said fuse, from overheating, said fuse characterized by:

two electrically conductive terminal block means, for electical connection to electrodes carried by said substrate, said two block means in close proximity to one another, in axial alignment, but in a spaced apart relationship, and having holes extending therethrough; and

an electrically conductive fusible link means electrically interconnecting said two terminal block means so as to complete an electric circuit, whereby said fusible link means melts under a condition of elevated temperature and molten material from said fusible link means is drawn into said holes in said terminal block means by capillary action, thereby breaking said electric circuit.

7. The fuse of claim 6 wherein said fusible link means is connected to said two terminal block means with a solder having a lower melting point than the melting point of said fusible link.

8. The fuse of claim 7 wherein said fusible link means is a piece of solder.

9. The fuse of claim 6 further characterized by:

said terminal blocks being in the shape of rectangular parallelepipeds, and said fusible link being soldered to said terminal blocks with solder having a melting point lower than the melting point of said fusible link.