Thermally decoupling fuse holder and assembly

• US 20060197647A1
• Filed: 03/03/2005
• Published: 09/07/2006
• Est. Priority Date: 03/03/2005
• Status: Active Grant

• Current Assignee: Gordon T. Dietsch, Stephen J. Whitney, Vincent Minh-Tu Tran
• Original Assignee: Gordon T. Dietsch, Stephen J. Whitney, Vincent Minh-Tu Tran
• Inventors: Whitney, Stephen J., Tran, Vincent Minh-Tu, Dietsch, Gordon T.
• Granted Patent: US 7,564,337 B2
• Time in Patent Office: Days
• US Class Current: 337/297
• CPC Class Codes: H01H 2085/0414 Surface mounted fuses
• CPC Class Codes: H01H 2085/2085 Holders for mounting a fuse on a printed circuit
• CPC Class Codes: H01H 85/0418 with ferrule type end contacts
• CPC Class Codes: H01H 85/202 for fuses with ferrule type end contacts
• CPC Class Codes: H05K 2201/062 Means for thermal insulation, e.g. for protection of parts
• CPC Class Codes: H05K 2201/10181 Fuse
• CPC Class Codes: H05K 2201/1031 Surface mounted metallic connector elements
• CPC Class Codes: H05K 2201/10386 Clip leads; Terminals gripping the edge of a substrate
• CPC Class Codes: H05K 2201/10636 Leadless chip, e.g. chip capacitor or resistor
• CPC Class Codes: H05K 2201/10757 Bent leads
• CPC Class Codes: H05K 2201/10946 Leads attached onto leadless component after manufacturing the component
• CPC Class Codes: H05K 3/301 by means of a mounting structure H05K3/325 takes precedence
• CPC Class Codes: H05K 3/3426 characterised by the leads
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

In one aspect of the present invention, subminiature fuses are soldered to a PCB via clips attached to the fuse end caps. The clips are physically attached to the PCB pads, enabling the fuse to be replaced if needed and providing thermal decoupling between the fuse and the heating sinking solder/PCB pads. The fuse and clips can also be picked and placed in one operation. In another aspect, improved fuse clips are provided that include tabs that separate the housing portions of the clips from the heating sinking solder/PCB pads. Such improved clips further enhance thermal decoupling. In a further aspect, an improved fuse is provided, in which the thermal decoupling tabs just described are provided directly with the fuse. In yet a further aspect, a thermally insultive fuse body is provided to further decouple the fuse element from its surroundings.

Claims

1. A printed circuit board (“

PCB”

) fuse assembly comprising.

a first housing portion configured to hold a first terminal of a fuse;

a first tab extending from the first housing portion, the first tab soldered to the PCB via a first solder joint and having a length such that the first solder joint is thermally decoupled from the first housing portion;

a second housing portion configured to hold a second terminal of the fuse; and

a second tab extending from the second housing portion, the second tab soldered to the PCB via a second joint and having a length that at least partially thermally decouples the second solder joint from the second housing portion.

2. The PCB fuse assembly of claim 1, wherein the length of the first tab is substantially the same as the length of the second tab.

3. The PCB fuse assembly of claim 1, which includes a fuse held by the first and second housing portions.

4. The PCB fuse assembly of claim 1, wherein the fuse is of a type selected from the group consisting of:

midget, 2AG, 3AG, 3AB, 5×

20 mm, Nano²®

, Pico®

SMF and chip fuses.

5. The PCB fuse assembly of claim 1, wherein the first and second tabs are soldered to the PCB via a process selected from the group consisting of:

wave soldering and reflow soldering.

6. The PCB fuse assembly of claim 1, wherein the first and second tabs are soldered to the PCB such that the first and second housing portions (i) contact the PCB or (ii) are spaced apart from the PCB.

7. The PCB fuse assembly of claim 1, wherein the first and second solder joints reside (i) between the PCB and the first and second housing portions, respectively or (ii) adjacent to the first and second housing portions, respectively.

8. The PCB fuse assembly of claim 1, wherein the first and second tabs are (i) formed integrally with the first and second housing portions respectively, or (ii) are connected to the first and second housing portions, respectively.

9. The PCB fuse assembly of claim 1, wherein the housing portions and the tabs are made of a material selected from the group consisting of:

a conductive material, ceramic, glass, polymer, brass, spring brass, copper, beryllium-copper, phosphor-bronze, steel, nickel, nickel alloy, tin, tin-lead, silver, gold, palladium, palladium alloy and rhodium.

10. The PCB fuse assembly of claim 1, wherein the PCB is made of a material selected from the group consisting of FR-4 material, ceramic, flexible material, cross-linked material, glass-epoxy composite, ceramic, and polymer material.

11. The PCB fuse assembly of claim 1, wherein the first and second housings are spaced apart on the PCB a distance corresponding to at least one of a length of the fuse and the length of the tabs.

12. The PCB assembly of claim 1, wherein the first and second tabs are spaced apart on the PCB according to a distance that a plurality of conductive pads on the PCB are spaced apart.

13. The PCB fuse assembly of claim 1, wherein the first and second housing portions each include a base and at least one wall angled therefrom, the tabs each extending (i) in at least a substantially parallel direction with respect to the corresponding base or (ii) in at least a substantial perpendicular direction with respect to the base.

14. A fuse assembly comprising:

a first clip holding a first terminal of a fuse; and

a second clip holding a second terminal of the fuse, wherein the first clip, second clip and fuse are configured such that (i) they may be picked and placed when assembled and (ii) the fuse spaces the first and second clips apart as needed according to a distance that a plurality of conductive pads or a printed circuit board (“

PCB”

) are spaced apart.

15. The fuse assembly of claim 14, wherein the first and second clips include first and second thermally decoupling tabs, respectively, the fuse spacing the first and second tabs apart as needed according to the distance that the plurality of conductive pads on the PCB are spaced apart.

16. The fuse assembly of claim 15, wherein the first and second clips each include a base and at least one wall angled therefrom, the tabs each extending (i) in at least a substantially parallel direction with respect to the corresponding base or (ii) in at least a substantially perpendicular direction with respect to the corresponding base.

17. The fuse assembly of claim 15, wherein the first and second tabs are soldered to the PCB such that fuse housing portions of the first and second clips (i) contact the PCB or (ii) are spaced apart from the PCB.

18. The fuse assembly of claim 14, wherein the fuse is of a type selected from the group consisting of:

midget, 2AG, 3AG, 3AB, 5×

20 mm, Nano²®

, Pico®

SMF and chip fuses.

19. The fuse assembly of claim 14, wherein the first and second clips are soldered to the PCB via a process selected from the group consisting of:

wave soldering and reflow soldering.

20. A fuse for a printed circuit board (“

PCB”

) comprising;

.

a body;

a fuse element located within the body;

first and second conductive end caps coupled to the body and in electrical communication with the fuse element; and

a first tab extending from the first end cap and a second tab extending from the second end cap, the tabs configured so that when assembled to the PCB the end caps are at least partially thermally decoupled from first and second solder joints connecting the tabs to the PCB.

21. The fuse of claim 20, wherein the first and second tabs are (i) formed integrally with the first and second end caps, respectively or (ii) are connected to the first and second end caps, respectively.

22. The fuse of claim 20, wherein the housing is elongated in a direction and the tabs extend from the end caps (i) at least substantially parallel to the direction or (ii) at least substantially perpendicular to the direction.

23. The fuse of claim 20, wherein the body is a thermally non-conductive body.

24. The fuse of claim 23, wherein the body comprises a glass material.

25. The fuse of claim 24, wherein the body comprises a boro-silicate material.

26. The fuse of claim 24, wherein the body comprises a soda-lime material.

27. The fuse of claim 23, wherein the body comprises a polymer material.