US2111628A - Electric fuse - Google Patents

Electric fuse Download PDF

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Publication number
US2111628A
US2111628A US120748A US12074837A US2111628A US 2111628 A US2111628 A US 2111628A US 120748 A US120748 A US 120748A US 12074837 A US12074837 A US 12074837A US 2111628 A US2111628 A US 2111628A
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US
United States
Prior art keywords
fuse
stem
strip
central
portions
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.)
Expired - Lifetime
Application number
US120748A
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English (en)
Inventor
Hoban Hugh Charles
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.)
WT Henleys Telegraph Works Co Ltd
Original Assignee
WT Henleys Telegraph Works Co Ltd
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 WT Henleys Telegraph Works Co Ltd filed Critical WT Henleys Telegraph Works Co Ltd
Application granted granted Critical
Publication of US2111628A publication Critical patent/US2111628A/en
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
    • 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
    • H01H85/055—Fusible members
    • H01H85/08—Fusible members characterised by the shape or form of the fusible member
    • H01H85/10—Fusible members characterised by the shape or form of the fusible member with constriction for localised fusing

Definitions

  • fuse element is not to be confused with elements of the well known bimetallic type in which there is present lo place less than that of the remaining parts, genan insertion of a metal or alloy having a relal erally the end or stem portions of the element. iively low melting p 'fl- Such a sertion is so This has the effect of increasing the resistance p opo t o ed e at ve to the adjacent Parts o e of that portion so that, under working condielement that it will melt in the event of the sustions, it assumes a higher temperature than the tained overload conditions.
  • circuit conditions with which they are designed to with this object in vie we provide a fuse elecope, melt and break the junctions between the ment comprising a central fusible portion and centre and stem p rts of t e e ment before fustem portions, in which the central portion is o of the ce t al po t on occurs.
  • each Stem wire and uniting the overlapping portions by an P01111011 being in the form of expanded metal insertion having a thickness of, approximately, that is to say, in the form of sheet metal cut and one. fifth to one seventh the length of the over bent or stretched to form a lattice.
  • FIG. 1 is a side elevation of one form of fuse more intimate contact with the surrounding coolelement.
  • Figure 1A is a fragmentary e io ing medium and, consequently, facilitates the partly in section and on an enlarged scale, of the as transfer of heat from the stem to the medium. elements shown in Figure 1,
  • Figure 2 is a plan view of the element shown in Figure 1
  • Figure 3 is a cross-sectional view, taken on the line IlI-III of Figure 1, of the element shown therein.
  • Figure 3A is a cross-sectional view on an enlarged scale, taken on the line IIIA-IIIA of Figure 1A, of the element shown therein,
  • Figure 4 is a perspective view of a second form of fuse element
  • Figure 5 is a side elevation of the element shown in Figure 4,
  • Figure 6 is a plan view of the element shown in Figures 4 and 5
  • Figure 7 is a cross-sectional view, taken on the line VII-VII of Figure 5, of the element shown therein,
  • Figure 8 is a cross sectional elevation of one half of a cartridge fuse fitted with elements of the form shown in Figures 4, 5, 6, and 7, and
  • Figure 9 is an end elevation of the fuse shown in Figure 8.
  • Figure 10 is a graph of the relationship between fusing current and time which demonstrates the advantage yielded by the improved construction of element of the form shown in Figures 1, 2, and 3.
  • the element comprises a central portion I' in the form of a wire of circular cross section and stem portions 2 in the form of thin strips of metal of greater current carrying capacity.
  • the central portion overlaps the stem portions for a distance along the stem equal to approximately three times the diameter of the wire and these overlapping parts are united by soldering them together in such a way that each overlapping part of the wire is spaced apart from the strip by the solder 3, a distance approximately equal to half the diameter of the wire.
  • a convenient way of ensuring correct spacing is to form a small upstanding projection on the extremity of the strip, as shown at l in Figure 1.
  • the width of the insertion between the overlapping parts is determined by the diameter of the wire, the soldering metal being allowed to form a natural meniscus between the lateral surface of the wire and the adjacent fiuxed surface of the strip. It is preferred to form both the central and stem portions of silver.
  • suitable materials for the thermal resistance insertions are pure lead solder, and a solder consisting of an alloy of lead containing a small percentage of tin.
  • central fusible portion is shown as a wire of circular cross-section.
  • This form is advantageous in that it reduces the area of the radiating surface of the central portion to a minimum but it will be obvious that central fusible portions of other form, for instance, wire of noncircular crosssection or narrow metal strip, may Just as readily be used if desired.
  • the stem portions 2 are in the form of thin fiat strips, but in Figures 4 to '7 inelusive the stem portions 2 are of a modified form tive to the strip and is preferably parallel with the edge of the strip, as shown.
  • the slits of each group are shown to be in line with the slits of the other group but this is not essential. It will be seen that these slits 3 and l divide two short lengths of the stem into three parts. At each of these places the two outer parts (I or I) are displaced in one direction out of the plane of the strip and the intervening part (9 or III) is displaced in the opposite direction.
  • outer parts I at one place are preferably displaced in the opposite direction to the outer parts I at the adjacent place, as is clearly shown in Figure 4.
  • the number of groups and the number of slits per group may vary and may be more or less than in the example shown in the drawings.
  • FIG 8 is shown one half of a cartridge fuse employing a number of elements similar to that described with reference to Figures 4, 5, 8, and '7; the other half of the fuse, being exactly similar, has been omitted from the drawings.
  • the fuse comprises a barrel ii of ceramic material provided with a number of passages l2 extending from end to end thereof.
  • a metal cap I! is positioned on each end of the barrel II and is secured thereto by means of a cemented joint I. This cap is provided with apertures corresponding to the passages II.
  • each e I! is disposed a pair of elements it.
  • the central parts I of these elements are bunched together and located in the centre of the passage but the stems 2 diverge from one another so that near the end of the passage they lie on opposite sides thereof.
  • the extremities of the stems pass through the apertures in the cap It and are bent over as shown at It and held in contact with the outer face of the cap by soldering or welding and/or by means of an outer cap I! which fits over the inner cap and carries the contact blades l8.
  • the ends of the passages I! are plugged with asbestos plugs l9 and an asbestos pad is inserted between the bent over ends of the elements I! and the outer metal cap H, in order to reduce the transmission of heat from the interior of the fuse to the contact blades.
  • the invention is particularly advantageous when applied to fuse elements of cartridge fuses where the element is embedded in a material having a thermal conductivity that is low compared with that of the metal of the element. Normally the major part of the heat generated in the element will be conveyed to the terminals of the fuse. By the improved method of uniting the stem and central portions, this transmission of heat may be reduced and the heat generated be dammed in the centre part of the element with the result that the fusing factor is considerably decreased.
  • the temperature of the fuse cap was '71.5 0., that of the fuse contact 64.2" C. and that of the circuit contact 51.5 C. -In' the latter case, with the same ambient temperature, the temperatures at corresponding placeswere considerably lower, being 62.6'' C. at the fuse cap, 585 C.
  • a fuse element for an electric fuse com-.
  • each of said means being an insertionof substantial thickness of a metallic material having a relatively high thermal resistance.
  • a fuse element for an electric fuse comprising a central portion of silver injwhich fusion is initiated, stem portions of silver and means for electrically connecting said stem poix tions to the ends of said central portion, each of said meanscomprising an insertion of sub-' stantial thickness of metallic material having a thermal resistance considerably higher than that of silver.
  • a fuse element for an electric fuse comprising a central fusible portion of wire orv narrow strip and stem portions of relatively wide strip, at least part of each stem portion being in the form of expanded metal.
  • a fuse element for an electric fuse comprising a central fusible portion of wire or narrow strip and stem portions, said stem portions each consisting of relatively wide metal strip having, near the central portion of the element, a plurality of groups of parallel slits extending longitudinally of the strip and having the metal on both sides of each slit displaced from the normal surface of the strip to form a lattice.
  • a fuse element for an electric fuse comprising a central portion of wire or strip in which fusion is initiated, stem portions which are of relatively wide strip and comprise parts in the form of expanded metal, and means serving to connect said central portion electrically to and space it to a pre-determined extent from, each of said stem portions, each of said means-being an insertion of substantial thickness of a metallic material having a relatively high thermal resistance.
  • a fuse element for an electric fuse including a central portion in which, under any circuit conditions with which the fuse is designed to cope, fusion is initiated, a pair of stem portions, and a pair of heat barriers, consisting of metallic material of which the. thermal resistance is relatively high compared with that of the central and stem portions, one of said barriers being inserted between, and connecting together, one end of said central portion and one of said stem portions and the other of said barriers being inserted between, and connecting together, the other end of said central portion andthe other of said stemportions.

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  • Fuses (AREA)
US120748A 1936-01-21 1937-01-15 Electric fuse Expired - Lifetime US2111628A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1929/36A GB467684A (en) 1936-01-21 1936-01-21 Improvements in or relating to electric fuses

Publications (1)

Publication Number Publication Date
US2111628A true US2111628A (en) 1938-03-22

Family

ID=9730492

Family Applications (1)

Application Number Title Priority Date Filing Date
US120748A Expired - Lifetime US2111628A (en) 1936-01-21 1937-01-15 Electric fuse

Country Status (5)

Country Link
US (1) US2111628A (enrdf_load_stackoverflow)
BE (1) BE419569A (enrdf_load_stackoverflow)
DE (1) DE681389C (enrdf_load_stackoverflow)
FR (1) FR816591A (enrdf_load_stackoverflow)
GB (1) GB467684A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2800554A (en) * 1953-06-23 1957-07-23 E M P Electric Ltd Electric fuses
US2827532A (en) * 1955-10-28 1958-03-18 Frederick J Kozacka Current-limiting low impedance fuses for small current intensities
US3140371A (en) * 1959-12-02 1964-07-07 Siemens Ag Fuse constructions
US20050001710A1 (en) * 2003-07-01 2005-01-06 Takahiro Mukai Fuse, battery pack using the fuse, and method of manufacturing the fuse

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2800554A (en) * 1953-06-23 1957-07-23 E M P Electric Ltd Electric fuses
US2827532A (en) * 1955-10-28 1958-03-18 Frederick J Kozacka Current-limiting low impedance fuses for small current intensities
US3140371A (en) * 1959-12-02 1964-07-07 Siemens Ag Fuse constructions
US20050001710A1 (en) * 2003-07-01 2005-01-06 Takahiro Mukai Fuse, battery pack using the fuse, and method of manufacturing the fuse
WO2005004183A1 (en) * 2003-07-01 2005-01-13 Matsushita Electric Industrial Co., Ltd. Fuse, battery pack using the fuse, and method of manufacturing the fuse
US7106165B2 (en) 2003-07-01 2006-09-12 Matsushita Electric Industrial Co., Ltd. Fuse, battery pack using the fuse, and method of manufacturing the fuse
CN1322524C (zh) * 2003-07-01 2007-06-20 松下电器产业株式会社 熔断器、使用该熔断器的电池组及制造该熔断器的方法

Also Published As

Publication number Publication date
FR816591A (fr) 1937-08-11
DE681389C (de) 1939-09-22
GB467684A (en) 1937-06-22
BE419569A (enrdf_load_stackoverflow)

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