SOLDERLESS SURFACE MOUNT FUSE

• US 20100245025A1
• Filed: 03/25/2009
• Published: 09/30/2010
• Est. Priority Date: 03/25/2009
• Status: Active Grant

• Current Assignee: Littelfuse Incorporated
• Original Assignee: Littelfuse Incorporated
• Inventors: Song, John, de Leon, Conrado, Olan, Edgardo, Semana, John Emannuel, Dietsch, Gordon T., Whitney, Stephen J.
• Granted Patent: US 8,937,524 B2
• Time in Patent Office: Days
• US Class Current: 337/290
• 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 69/02 Manufacture of fuses
• CPC Class Codes: H01H 85/0418 with ferrule type end contacts
• CPC Class Codes: H01H 85/055 Fusible members
• CPC Class Codes: H01H 85/08 characterised by the shape or form of the fusible member
• CPC Class Codes: H01H 85/157 Ferrule-end contacts
• CPC Class Codes: H01H 85/165 Casings
• CPC Class Codes: H05K 3/3421 Leaded components
• CPC Class Codes: Y10T 29/49107 Fuse making

Abstract

A surface mount fuse in one embodiment includes an insulative body, first and second conductive and caps attached to the insulative body, each end cap defining an aperture, and a fuse element extending (i) through the insulative body and the apertures and (ii) along outside surfaces of the first and second conductive end caps in such a way that solder used to attach the first and second conductive end caps to an external medium also fastens the fuse element to the first and second end caps.

Claims

1. A surface mount fuse comprising:

an insulative body;

first and second conductive end caps attached to the insulative body, each end cap defining an aperture; and

a fuse element extending (i) through the insulative body and the apertures and (ii) along outside surfaces of the first and second conductive end caps in such a way that solder used to attach the first and second conductive end caps to an external medium also fastens the fuse element to the first and second end caps.

2. The surface mount fuse of claim 1, wherein additional solder to connect the fuse element to the first and second conductive end caps is not provided.

3. The surface mount fuse of claim 1, wherein the fuse element is bent to extend along the outside surfaces of the second end caps.

4. The surface mount fuse of claim 1, wherein the fuse element extends axially away from the outside surfaces of the first and second end caps for attachment by the solder to the external medium.

5. The surface mount fuse of claim 1, wherein the fuse element extends axially under the first and second end caps, underneath the end caps.

6. The surface mount fuse of claim 1, wherein the fuse element is one of a wire and a strip.

7. The surface mount fuse of claim 1, wherein the fuse element is coiled along the outside surface of the first and second end caps.

8. The surface mount fuse of claim 1, wherein the insulative housing is made of one of ceramic and glass, melamine or glass-epoxy composite.

9. The surface mount fuse of claim 1, wherein the solder is at least substantially prevented from contacting the fuse element inside of the insulative housing.

10. A surface mount fuse comprising;

a insulative body;

first and second inner conductive end caps connected to the insulative body;

first and second outer conductive end caps mated with the first and second inner conductive end caps, respectively; and

a fuse element extending within the housing, crimped at a first end between the mating first inner and outer conductive end caps, and crimped at a second end between the mating second inner and outer conductive end caps.

11. The surface mount fuse of claim 10, the first end of the fuse element crimped between the mating first inner and outer conductive end caps at a first point that is diagonally opposite to a second point at which the second end of the fuse element is crimped between the mating second inner and outer conductive end caps.

12. The surface mount fuse of claim 10, wherein the fuse element is at least one of:

(i) a wire;

(ii) a strip; and

(iii) a coil.

13. The surface mount fuse of claim 10, wherein at least one of:

(i) the mating inner and outer conductive end caps are connected solderlessly; and

(ii) the fuse element is crimped solderlessly.

14. The surface mount fuse of claim 10, wherein at least one of:

(i) the first and second outer conductive end caps are press-fitted onto the insulative housing; and

(ii) the first and second outer conductive end caps are press-connected to the first and second inner conductive end caps, respectively.

15. The surface mount fuse of claim 10, wherein the first and second inner conductive end caps each define an aperture that allows the fuse element to pass through the inner conductive end caps to be crimped in place.

16. A surface mount fuse comprising:

a insulative housing;

first and second conductive end caps attached to the insulative housing, the first conductive end cap defining a first aperture, the second conductive end cap defining a second aperture; and

a fuse element fitted within the housing and having first and second ends abutting inside surfaces of the first and second conductive end caps so as to at least substantially cover the first and second apertures, such that solder used to solder the first and second conductive end caps to an external medium also solders the first and second fuse element ends to the first and second end caps, respectively.

17. The surface mount fuse of claim 16, wherein additional solder to connect the fuse element to the first and second conductive end caps is not provided.

18. The surface mount fuse of claim 16, wherein the solder is at least substantially prevented from flowing into the insulative housing.

19. The surface mount fuse of claim 16, wherein the fuse element is a strip of metal having a width that is at least as large as a diameter of the first and second apertures.

20. The surface mount fuse of claim 16, wherein the first and second ends of the fuse element are each bent at least one time so as to at least substantially cover the first and second apertures.

21. The surface mount fuse of claim 16, wherein the fuse element at each of the first and second ends is bent in two directions.

22. The surface mount fuse of claim 21, wherein the first and second ends of the fuse element are bent so as to at least substantially cover the first and second apertures.

23. A method for a surface mount fuse having a housing and first and second end caps, the method comprising:

placing the surface mount fuse onto a printed circuit board (“

PCB”

) such that the first and second end caps are aligned with first and second contacts located on the PCB; and

soldering the first and second end caps to the first and second contacts such that (i) the first and second end caps are secured to the first and second contacts and (ii) a fuse element located within the housing is secured for the first time with solder to the first and second end caps.

24. The method of claim 23, which includes thermally collapsing a glass, at first and second ends forming the first and second end caps, about the fuse element prior to placing the surface mount fuse onto the PCB.

25. The method of claim 24, which includes plating the first and second ends forming the first and second end caps prior to placing the surface mount fuse onto the PCB.

26. The method of claim 23, which includes crimping the fuse element between the housing and the first and second end caps prior to placing the surface mount fuse onto the PCB.

27. The method of claim 23, which includes crimping the fuse element between first and second portions of each of the first and second end caps prior to placing the surface mount fuse onto the PCB.