EP0518510A2 - Elektrische Schmelzsicherungen - Google Patents

Elektrische Schmelzsicherungen Download PDF

Info

Publication number
EP0518510A2
EP0518510A2 EP92304672A EP92304672A EP0518510A2 EP 0518510 A2 EP0518510 A2 EP 0518510A2 EP 92304672 A EP92304672 A EP 92304672A EP 92304672 A EP92304672 A EP 92304672A EP 0518510 A2 EP0518510 A2 EP 0518510A2
Authority
EP
European Patent Office
Prior art keywords
housing
solder
end caps
caps
fuse
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.)
Granted
Application number
EP92304672A
Other languages
English (en)
French (fr)
Other versions
EP0518510B1 (de
EP0518510A3 (en
Inventor
Martin David Bacon
Peter John "The Cedars" Drayton
Rognvald Ridley Peterson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cooper Industries LLC
Original Assignee
Cooper Industries LLC
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Cooper Industries LLC filed Critical Cooper Industries LLC
Priority to JP15342192A priority Critical patent/JPH05198248A/ja
Publication of EP0518510A2 publication Critical patent/EP0518510A2/de
Publication of EP0518510A3 publication Critical patent/EP0518510A3/xx
Application granted granted Critical
Publication of EP0518510B1 publication Critical patent/EP0518510B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H69/00—Apparatus or processes for the manufacture of emergency protective devices
    • H01H69/02—Manufacture of fuses
    • 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

  • the present invention relates to miniature electrical fuses and more particularly to such fuses in which the fusible element is located within a tubular housing of an insulating material and connected between electrically conducting end caps which close off the opposite ends of the tubular housing and have electrical lead wires connected thereto to permit the fuse to be connected into a circuit without use of a fuse holder.
  • the invention is particularly concerned with problems arising from securing the electrical wires to the end caps in miniature fuses.
  • the lead wires are generally welded or staked to external or secondary caps which are pushed on over the main end caps after manufacture of the main body of the fuse. This is because attempts to resistance weld lead wires directly to the main end caps give rise to a number of problems. Particular problems which occur are weakness of the lead attachment; distortion of the fusible element during welding which causes variation in the blowing characteristics of the fuse or loss of breaking capacity; and furthermore movement of solder fluidised during the welding process causes globules or streamers of solder to enter the fuse housing and affect the fuse performance.
  • the invention provides a method of manufacturing a miniature electrical fuse having a fusible element located within a tubular housing made of insulating material, the element being connected between electrically conducting end caps which close off the opposite ends of the housing, and the end caps having electrical lead wires connected thereto to permit the fuse to be connected into a circuit without use of a fuse holder, said method comprising forming a sub-assembly by uniting each end of the tubular housing and the element to the end caps with a solder alloy whilst maintaining an axial force on each end cap to urge each end cap into direct mechanical contact with the pertaining end face of the housing such that solder is substantially absent from the site of said direct mechanical contact, and, subsequently to the solder having solidified, simultaneously resistance welding the lead wires directly to the end caps of the sub assembly using opposed thrust forces which via the end caps are transmitted through the said direct mechanical contacts to the tubular housing, wherein the end caps are selected to have comparatively thick base portions and thin side walls, the thickness ratio being within the range
  • the invention also relates to constructional features of the fuse and according to a further aspect therefore the invention provides a miniature electrical fuse in which the fusible element is located within a tubular housing of an insulating material and connected between electrically conducting end caps which close off the opposite ends of the tubular housing wherein an electrical lead wire is secured to each end cap and the thickness of at least that part of the base of each end cap to which a lead wire is secured is greater than the thickness of the side wall of the cap in a ratio between 1.3 and 2.1 to 1.
  • a fusible element comprising a helical wire 1 wound on an insulating support 2 is axially located in a cylindrical tubular glass housing 3 whose ends are closed off by electrically conducting metal end caps 4.
  • the housing 3 could alternatively be made of ceramic or a filled plastic material and the fusible element 1 could alternatively be a slant wire, an axial wire, or other element design known in the art.
  • the housing 3 may be filled with a suitable material e.g. quartz grains, ceramic particles, ceramic wool, ceramic cloth, ceramic paper, polymer granules, inorganic or organic materials intended to release arc-quenching substances when heated, or solid matrix ceramic materials.
  • the ends of the tubular housing 3 are made accurately plane parallel and perpendicular to the axis of the housing so that when the solder initially located within each end cap 4 is melted and the end cap is pushed on to the housing 3 during the assembly of the fuse, direct mechanical contact is achieved between the end cap and the end faces of the housing as shown at 5.
  • this accuracy of the tube end faces can be achieved by cutting with a diamond wheel.
  • this can be achieved by end grinding after firing.
  • a flux is used initially to melt the solder into the caps 4 prior to assembly of the fuse, but after solder solidification and prior to such assembly the flux is removed by immersion in a solvent. This ensures that the assembled fuse has a solid metal joint between the end cap and the end faces of the tubular housing, without enclosures of solidified flux. Such enclosures of flux can lead to distortion of the fuse during the subsequent resistance welding process as the enclosures soften at comparatively low temperatures.
  • solder joint between the housing 3 and the side wall of the end caps is shown at 6 and the solder joint to the fuse wire is shown at 7. Solder is substantially squeezed out from and therefore is effectively absent from the site 5 of direct mechanical contact between housing 3 and end caps 4.
  • the solder is selected to have a comparatively high melting point (for example 180°C or greater) and preferably is an alloy of lead in the range 77-90% and tin in the range 23%-10%.
  • a comparatively high melting point for example 180°C or greater
  • the solder is selected to have a comparatively high melting point (for example 180°C or greater) and preferably is an alloy of lead in the range 77-90% and tin in the range 23%-10%.
  • One particular alloy which is suitable is 85% lead and 15% tin.
  • Other alloys containing tin, lead, possibly with antimony and silver in varying proportions, may also be utilised.
  • each end cap 4 is thicker than the side wall of the cap preferably within the ratio 1.3 to 1 and 2.1 to 1.
  • the thick base of the end caps is provided to withstand the subsequent resistance welding process whereas the side wall of the end caps is comparatively thin and elastic so that during the solder cooling process the contraction of the side wall and solder joint 6 does not lead to excessive forces on the frangible side walls of the housing 3.
  • the thickness of the base of each end cap is typically 0.5 to 0.72mm and the side wall thickness is typically 0.3 to 0.45mm.
  • the lead wires may be between 0.4 and 1.0mm in diameter and made of tin plated copper or tin plated copper clad steel.
  • a clamp type electrode is simultaneously fitted to the side wall of each end cap 4 and each lead wire 8 is gripped by an electrode and urged axially into engagement with the pertaining end cap to form the welds 9.
  • the opposing axial forces from both lead wires 8 are transmitted by the comparatively thick end walls of the end caps 4 and their circumferential abutment with the end faces of the housing 3 to the housing itself.
  • the thermal effects of the resistance welding process are greatest at the outermost surface of the end walls of the end caps 4 where the welds 9 are formed.
  • the lead wires 8 are therefore simultaneously fitted directly to the end caps 4 without disturbing the pre-assembled main portion of the fuse.
  • each end cap to which the lead wire 8 is attached may be of increased thickness as indicated by the broken line configuration 4a.
  • the central portion to which the lead wire is welded may be of thickness between 0.5 and 1.0mm.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Fuses (AREA)
EP19920304672 1991-06-13 1992-05-22 Elektrische Schmelzsicherungen Expired - Lifetime EP0518510B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15342192A JPH05198248A (ja) 1991-06-13 1992-06-12 電気フューズ

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9112726 1991-06-13
GB919112726A GB9112726D0 (en) 1991-06-13 1991-06-13 Electrical fuses

Publications (3)

Publication Number Publication Date
EP0518510A2 true EP0518510A2 (de) 1992-12-16
EP0518510A3 EP0518510A3 (en) 1994-10-26
EP0518510B1 EP0518510B1 (de) 1997-09-03

Family

ID=10696589

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920304672 Expired - Lifetime EP0518510B1 (de) 1991-06-13 1992-05-22 Elektrische Schmelzsicherungen

Country Status (3)

Country Link
EP (1) EP0518510B1 (de)
DE (1) DE69221950T2 (de)
GB (1) GB9112726D0 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007140794A1 (de) * 2006-06-02 2007-12-13 Mbl Josef Leyerer Kg Anschlusskappe für ein elektrisches bauelement, verfahren zur herstellung dafür, elektrisches bauelement und verfahren zur herstellung dafür
CN114730679A (zh) * 2019-11-21 2022-07-08 力特保险丝公司 具有正温度系数装置和备用熔断器的电路保护装置

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8501677A (nl) * 1985-06-11 1987-01-02 Littelfuse Tracor Werkwijze voor het bevestigen van een aansluitdraad aan een metalen eindkap van een smeltveiligheid.
US4924203A (en) * 1987-03-24 1990-05-08 Cooper Industries, Inc. Wire bonded microfuse and method of making
US4866411A (en) * 1988-03-25 1989-09-12 Caddock Richard E Film-type cylindrical resistor, and method of making it

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007140794A1 (de) * 2006-06-02 2007-12-13 Mbl Josef Leyerer Kg Anschlusskappe für ein elektrisches bauelement, verfahren zur herstellung dafür, elektrisches bauelement und verfahren zur herstellung dafür
CN114730679A (zh) * 2019-11-21 2022-07-08 力特保险丝公司 具有正温度系数装置和备用熔断器的电路保护装置

Also Published As

Publication number Publication date
EP0518510B1 (de) 1997-09-03
DE69221950D1 (de) 1997-10-09
GB9112726D0 (en) 1991-07-31
DE69221950T2 (de) 1998-02-19
HK1000773A1 (en) 1998-04-24
EP0518510A3 (en) 1994-10-26

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