FUSE WITH CAVITY FORMING ENCLOSURE

• US 20090102595A1
• Filed: 12/29/2008
• Published: 04/23/2009
• Est. Priority Date: 10/03/2005
• Status: Abandoned Application

• Current Assignee: Littelfuse Incorporated
• Original Assignee: Littlefuse Incorporated
• Inventors: Pachla, Timothy E., Dietsch, Gordon T.
• Application Number:
  US12/345,344
• Publication Number:
  US 20090102595A1
• Time in Patent Office: Days
• US Class Current: 337/297
• CPC Class Codes: H01H 2085/0412 specially adapted for being mounted on a printed circuit board
• CPC Class Codes: H01H 2085/0414 Surface mounted fuses
• CPC Class Codes: H01H 2085/0555 Input terminal connected to a plurality of output terminals, e.g. multielectrode
• CPC Class Codes: H01H 85/0086 use of a flexible body, e.g. inside the casing
• CPC Class Codes: H01H 85/0411 Miniature fuses
• CPC Class Codes: H01H 85/046 Fuses formed as printed circuits

Abstract

A surface mount fuse includes a substrate, a fuse element applied to the substrate, first and second terminals applied to substrate, first and second conductors connecting the fuse element electrically with the first and second terminals, and an enclosure coupled to the substrate, the enclosure covering the first and second conductors and defining a cavity overlying at least a portion of the fuse element, the cavity allowing for distortion of the fuse element upon its opening.

Claims

1. A surface mount fuse comprising:

a substrate;

a first fuse element applied to the substrate;

first and second terminals applied to the substrate and connected to the first fuse element;

first and second conductors connecting the first fuse element electrically with the first and second terminals;

a second fuse element applied to an opposite side of the substrate;

third and fourth terminals applied to the substrate and connected to the second fuse element;

third and fourth conductors connecting the second fuse element electrically with the third and fourth terminals; and

an enclosure coupled to the substrate, the enclosure covering the first and second conductors and defining a cavity overlying at least a portion of the fuse element, the cavity allowing for distortion of the first and second fuse elements upon opening.

2. The surface mount fuse of claim 1, wherein the substrate is made of a material selected from the group consisting of:

FR-4, epoxy resin, ceramic, resin coated foil, polytetrafluoroethylene, polyimide, glass and any combination thereof.

3. The surface mount fuse of claim 1, wherein at least one of the fuse elements, first and second terminals, and first and second conductors is made of at least one material selected from the group consisting of:

copper, tin, nickel, silver, gold, alloys thereof and any combination thereof.

4. The surface mount fuse of claim 1, wherein the fuse elements are offset and misaligned laterally with respect to each other.

5. The surface mount fuse of claim 1, wherein the first and second terminals extend along multiple surfaces of the substrate.

6. The surface mount fuse of claim 1, wherein the first and second terminals can be accessed from one side of the fuse.

7. The surface mount fuse of claim 1, wherein the first and second fuse elements connect to a common terminal.

8. The surface mount fuse of claim 1, wherein the surface mount fuse includes a deposition of a dissimilar metal on at least the first or second fuse element at a location desirable for opening.

9. The surface mount fuse of claim 1, wherein the first and second conductors narrow as they approach each other.

10. The surface mount fuse of claim 1, wherein the first and second fuse elements are arranged in a non-symmetrical manner on the substrate or within the enclosure.

11. The surface mount fuse of claim 1, wherein the cavity is at least partially filled with an arc-quenching material.

12. A surface mount fuse comprising:

a substrate;

a first fuse element applied to the substrate;

first and second terminals applied to the substrate and first and second conductors connecting the first fuse element electrically with the first and second terminals;

a second fuse element applied to an opposite side of the substrate;

third and fourth terminals applied to the substrate and connected to the second fuse element;

third and fourth conductors connecting the second fuse element electrically with the third and fourth terminals; and

an enclosure coupled to the substrate, the enclosure having a different footprint from the substrate and defining a cavity overlying at least a portion of the fuse element, the cavity allowing for mechanical distortion of the fuse element upon its opening.

13. The surface mount fuse of claim 12, wherein the cavity is at least partially filled with an arc-quenching material.

14. The surface mount fuse of claim 12, wherein the enclosure covers the first and second conductors.

15. The surface mount fuse of claim 12, wherein the first and second conductors and the third and fourth conductors are plated onto the substrate in a shape selected from the group consisting of serpentine, an X or a cross.

16. A surface mount fuse comprising:

a substrate;

a first fuse element applied to the substrate;

first and second terminals applied to the substrate;

first and second conductors connecting the first fuse element electrically with the first and second terminals;

a second fuse element applied to an opposite side of the substrate;

third and fourth terminals applied to the substrate and connected to the second fuse element;

third and fourth conductors connecting the second fuse element electrically with the third and fourth terminals; and

an enclosure coupled to the substrate, the enclosure defining a cavity overlying at least a portion of the first and second fuse elements, wherein the first and second conductors and the third and fourth conductors are in a shape selected from the group consisting of serpentine, an X or a cross.

17. The surface mount fuse of claim 16, wherein the first and second fuse elements have different ratings.

18. The surface mount fuse of claim 16, wherein the first and second terminals are (i) plated onto the substrate and the enclosure or (ii) plated onto the substrate only.

19. The surface mount fuse of claim 16, wherein each of the terminals extends around three sides of the substrate.

20. The surface mount fuse of claim 16, further comprising at least one additional fuse element applied to the substrate.