EP0822568A1 - Conductive epoxy fuse and method of making - Google Patents
Conductive epoxy fuse and method of making Download PDFInfo
- Publication number
- EP0822568A1 EP0822568A1 EP97111494A EP97111494A EP0822568A1 EP 0822568 A1 EP0822568 A1 EP 0822568A1 EP 97111494 A EP97111494 A EP 97111494A EP 97111494 A EP97111494 A EP 97111494A EP 0822568 A1 EP0822568 A1 EP 0822568A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- insulating body
- fusible element
- conductive epoxy
- fuse
- conductive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
- H01H85/02—Details
- H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
- H01H85/041—Fuses, i.e. expendable parts of the protective device, e.g. cartridges characterised by the type
- H01H85/0411—Miniature fuses
- H01H85/0415—Miniature fuses cartridge type
- H01H85/0418—Miniature fuses cartridge type with ferrule type end contacts
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
- H01H85/02—Details
- H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
- H01H85/05—Component parts thereof
- H01H85/143—Electrical contacts; Fastening fusible members to such contacts
- H01H85/157—Ferrule-end contacts
Definitions
- This invention relates to fuses and, in particular, to miniature fuses.
- Conventional miniature fuses are assembled by feeding a fusible element through a hollow insulating body and soldering end caps to the body/fusible element assembly.
- the solder performs the function of making an electrical connection of the element to the end caps and a mechanical connection of the end caps to the insulating body.
- Control of the soldering operation is most critical since variations in time, temperature and pressure, both individually and in combination, can cause a multitude of quality problems. Among them - solder splashes, solder blowouts, cold solder joints, flux stains, etc. These potential problems add substantially to the cost of manufacture by requiring both heavy investment in assembly equipment and costly inspection procedures. Additionally, manufacturing costs are increased because of high shrinkage rates.
- Another object of the present invention is to provide a fuse and a method of making the same which avoids the use of solder.
- a fuse which includes a hollow insulating body having opposed ends.
- a fusible element having opposed ends is disposed within the insulating body such that the opposed ends of the fusible element extend from and overlie the opposed ends of the insulating body.
- First and second conductive end caps enclose the respective opposed ends of the insulating body and the fusible element.
- Each of the end caps is connected to respective ends of the insulating body and the fusible element by a conductive epoxy wherein the conductive component comprises a noble metal.
- a noble metal as the conductive component of the conductive epoxy avoids any problems with oxide build up which could adversely affect the conductivity of the fuse. More specifically, oxides of noble metals are conductive and, accordingly, even if oxide formation occurs, such oxide formation will not adversely affect the conductivity of the fuse.
- the fusible element (or at least the exposed surfaces thereof) is also made of a noble metal and, advantageously, the same noble metal as the conductive component of the conductive epoxy.
- respective quantities of conductive epoxy are deposited into the end caps prior to assembling of the end caps onto the insulating body.
- respective quantities of conductive epoxy are applied to the opposing ends of the insulating body prior to assembling the end caps onto the insulating body.
- the respective ends of the fuse are heated to cure the epoxy.
- the ends of the fuse are heated simultaneously, i.e., the heating takes place after the fuse has been completely assembled.
- Figure 1 is a longitudinal cross sectional view of a fuse illustrating certain principles of the present invention.
- Figure 2 is an exploded perspective view of the elements constituting the fuse of Figure 1.
- the fuse 10 includes a hollow insulating body 11 which, in the embodiment shown, is substantially rectangular in shape. This shape is typical of fuses which are surface mounted, along with other components, on a printed wiring board. However, the insulating body 11 may assume any other appropriate shape, such as, for example, cylindrical as is common for socket mounted fuses used in many electronic assemblies.
- a fusible element 12 is positioned within the hollow insulated body 11 and extends from one end to the other end.
- the composition and structure of fusible element 12 is such that it fuses or melts when the current therethrough exceeds a predetermined amount.
- the ends 13, 13 of the fusible element 12 are partially wrapped around and overlie the insulating body.
- the fusible element 12 is in the form of a flat or circular wire although other shapes may be employed.
- a pair of end caps 14, 14 in the same shape as the insulating body 11 are provided, the end caps 14, 14 being designed to closely fit over the ends of the insulating body 11.
- Each of the end caps 14, 14 is made of metal so as to provide conductivity from one end cap 14 through the fusible element 12 to the other end cap 14.
- a conductive epoxy 15 is deposited in the end caps 14, 14.
- the ends of the insulating body may be coated with epoxy 15 by a suitable process, such as by dipping the ends into epoxy.
- the end caps 14, 14 are press fitted onto the insulating body 11 and the epoxy 15 is cured by heating it for a sufficient time.
- the epoxy is such that it cures at a temperature below the melting temperature of the fusible element 12.
- the conductive metal in the epoxy 15 forms a reliable electrical connection between the end caps 14, 14 and the insulating body 11, while at the same time the bonding capability of the epoxy 14 completes and assures a reliable mechanical connection of the end caps 14, 14 to the fusible element 12 and to the insulating body 11.
- the conductive component of the conductive epoxy 15 is a noble metal to avoid any problems with oxide build-up. For the same reason, it is preferable to also form the fusible element 12 or at least its external surfaces of a noble metal.
- the conductive metal in the epoxy 15 is silver and the fusible element 12 is also formed of or plated with silver.
- the end caps 14, 14 are made of silver plated brass; the fusible element 12 is made of silver plated copper; the insulating body 11 is made of ceramic; and the epoxy 15 includes silver flake.
Abstract
Description
Claims (10)
- A fuse (10) characterized by:a hollow insulating body (11) having opposed ends;a fusible element (12) having opposed ends, the fusible element (12) being disposed within the insulating body (11) such that the opposed ends of the fusible element (12) extend from and overlie the opposed ends of the insulating body (11); andfirst and second conductive end caps (14) enclosing the respective opposed ends of the insulating body (11) and the fusible element (12), each of the first and second end caps (14) being connected to the respective opposed ends of the insulating body (11) and of the fusible element (12) by a conductive epoxy (15) wherein the conductive component comprises a noble metal.
- The fuse of claim 1, characterized in that the fusible element (12) has outer surfaces and the outer surfaces are comprised of a noble metal.
- The fuse of claim 2, characterized in that the outer surfaces of the fusible element (12) and the conductive component of the conductive epoxy (15) are comprised of the same noble metal.
- The fuse of claim 3, characterized in that the noble metal is silver.
- A method of manufacturing a fuse (10), characterized by the steps of:(a) providing a hollow insulating body (11) having opposed first and second ends, a fusible element (12) having opposed first and second ends, and first and second end caps (14);(b) positioning the fusible element (12) within the hollow insulating body (11) such that the first and second ends of the fusible element (12) extend respectively from the first and second end of the insulating body (11) and overlie the insulating body (11);(c) assembling the first end cap (14) and a first quantity of a conductive epoxy (15) with the first end of the insulating body (11), the first quantity of conductive epoxy (15) interconnecting the first end cap (14), the first end of the insulating body (11) and first end of the fusible element (12);(d) heating the interconnected first end cap (14), first end of the insulating body (11) and first end of the fusible element (12) to cure the epoxy of the first quantity of conductive epoxy (15);(e) assembling the second end cap (14) and a second quantity of a conductive epoxy (15) with the second end of the insulating body (11), the second quantity of conductive epoxy (15) interconnecting the second end cap (14), the second end of the insulating body (11) and the second end of the fusible element (12); and(f) heating the interconnected second end cap (14), second end of the insulating body (11) and second end of the fusible element (12) to cure the epoxy of the second quantity of conductive epoxy (15).
- The method of claim 5, characterized in that step (c) includes depositing the first quantity of conductive epoxy (15) in the first end cap (14) prior to assembling the first end cap (14) to the first end of the insulating body (11), and step (e) includes depositing the second quantity of conductive epoxy (15) in the second end cap (14) prior to assembling the second end cap (14) to the second end of the insulating body (11).
- The method of claim 5, characterized in that step (c) includes applying the first quantity of conductive epoxy (15) to the first end of the insulating body (11) prior to assembling the first end cap (14) to the first end of the insulating body (11), and step (e) includes applying the second quantity of conductive epoxy (15) to the second end of the insulating body (11) prior to assembling the second end cap (14) to the second end of the insulating body (11).
- The method of any of claims 5 to 7, characterized in that the fusible element (12) has outer surfaces and the outer surfaces are comprised of a noble metal.
- The method of claim 8, characterized in that the outer surfaces of the fusible element (12) and the conductive component of the conductive epoxy (15) are comprised of the same noble metal, the nobel metal being preferably silver.
- The method of any of claims 5 to 9, characterized in that steps (d) and (f) are performed simultaneously.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US69381396A | 1996-08-01 | 1996-08-01 | |
US693813 | 1996-08-01 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0822568A1 true EP0822568A1 (en) | 1998-02-04 |
Family
ID=24786224
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97111494A Ceased EP0822568A1 (en) | 1996-08-01 | 1997-07-08 | Conductive epoxy fuse and method of making |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0822568A1 (en) |
JP (1) | JP3876054B2 (en) |
TW (1) | TW345672B (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002071432A1 (en) * | 2001-03-02 | 2002-09-12 | Wickmann-Werke Gmbh | Fuse component |
WO2006054847A1 (en) * | 2004-11-16 | 2006-05-26 | Std Co., Ltd | Subminiature surface mount device fuse |
WO2019217737A1 (en) * | 2018-05-09 | 2019-11-14 | Littelfuse, Inc. | Circuit protection devices formed by additive manufacturing |
Families Citing this family (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6147585A (en) * | 1997-01-30 | 2000-11-14 | Cooper Technologies Company | Subminiature fuse and method for making a subminiature fuse |
KR100644412B1 (en) | 2004-11-16 | 2006-11-10 | 주식회사 세화전자 | Method for fabricating subminiature surface mount device fuse |
US8368502B2 (en) | 2006-03-16 | 2013-02-05 | Panasonic Corporation | Surface-mount current fuse |
JP4687664B2 (en) * | 2007-02-15 | 2011-05-25 | パナソニック株式会社 | Surface mount type current fuse and manufacturing method thereof |
JP4682978B2 (en) * | 2006-12-28 | 2011-05-11 | パナソニック株式会社 | Surface mount type current fuse and manufacturing method thereof |
US8154376B2 (en) * | 2007-09-17 | 2012-04-10 | Littelfuse, Inc. | Fuses with slotted fuse bodies |
US8203420B2 (en) * | 2009-06-26 | 2012-06-19 | Cooper Technologies Company | Subminiature fuse with surface mount end caps and improved connectivity |
JP5789882B2 (en) * | 2011-06-02 | 2015-10-07 | Koa株式会社 | Manufacturing method of cylindrical current fuse |
US9558905B2 (en) | 2011-10-27 | 2017-01-31 | Littelfuse, Inc. | Fuse with insulated plugs |
EP2771899B1 (en) * | 2011-10-27 | 2017-01-11 | Littelfuse, Inc. | Fuse with insulated plugs |
US9202656B2 (en) | 2011-10-27 | 2015-12-01 | Littelfuse, Inc. | Fuse with cavity block |
CN104576252A (en) * | 2013-10-16 | 2015-04-29 | 斯玛特电子公司 | Surface-adhering fuses and structures of surface-adhering fuses |
TWI574292B (en) * | 2015-08-21 | 2017-03-11 | Ching Ho Li | Surface adhesion type fuse and manufacturing method thereof |
CN107507742B (en) * | 2017-07-23 | 2020-04-17 | 南京萨特科技发展有限公司 | Manufacturing tool and manufacturing method of tubular ultra-miniature fuse |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3374330A (en) * | 1966-04-19 | 1968-03-19 | Westinghouse Electric Corp | Current limiting fuse |
US3505630A (en) * | 1968-01-29 | 1970-04-07 | Micro Devices Corp | Fuse construction |
EP0199401A1 (en) * | 1985-04-04 | 1986-10-29 | Littelfuse Tracor B.V. | Fuse |
WO1991014279A1 (en) * | 1990-03-13 | 1991-09-19 | Morrill Glasstek, Inc. | Electrical component (fuse) and method of making it |
US5214406A (en) * | 1992-02-28 | 1993-05-25 | Littelfuse, Inc. | Surface mounted cartridge fuse |
GB2278743A (en) * | 1993-06-01 | 1994-12-07 | Soc Corp | Chip fuse |
-
1997
- 1997-06-30 TW TW086109158A patent/TW345672B/en not_active IP Right Cessation
- 1997-07-08 EP EP97111494A patent/EP0822568A1/en not_active Ceased
- 1997-07-31 JP JP20603097A patent/JP3876054B2/en not_active Expired - Lifetime
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3374330A (en) * | 1966-04-19 | 1968-03-19 | Westinghouse Electric Corp | Current limiting fuse |
US3505630A (en) * | 1968-01-29 | 1970-04-07 | Micro Devices Corp | Fuse construction |
EP0199401A1 (en) * | 1985-04-04 | 1986-10-29 | Littelfuse Tracor B.V. | Fuse |
WO1991014279A1 (en) * | 1990-03-13 | 1991-09-19 | Morrill Glasstek, Inc. | Electrical component (fuse) and method of making it |
US5214406A (en) * | 1992-02-28 | 1993-05-25 | Littelfuse, Inc. | Surface mounted cartridge fuse |
GB2278743A (en) * | 1993-06-01 | 1994-12-07 | Soc Corp | Chip fuse |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002071432A1 (en) * | 2001-03-02 | 2002-09-12 | Wickmann-Werke Gmbh | Fuse component |
US7320171B2 (en) | 2001-03-02 | 2008-01-22 | Wickmann-Werke Gmbh | Fuse component |
WO2006054847A1 (en) * | 2004-11-16 | 2006-05-26 | Std Co., Ltd | Subminiature surface mount device fuse |
WO2019217737A1 (en) * | 2018-05-09 | 2019-11-14 | Littelfuse, Inc. | Circuit protection devices formed by additive manufacturing |
Also Published As
Publication number | Publication date |
---|---|
JP3876054B2 (en) | 2007-01-31 |
TW345672B (en) | 1998-11-21 |
JPH10177835A (en) | 1998-06-30 |
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