United States Patent
`
`[19]
`
`[11] Patent Number:
`
`4,670,729
`
`0h
`
`[45] Date of Patent:
`
`Jun. 2, 1987
`
`[54] ELECTRICAL FUSE
`
`[75]
`
`Inventor:
`
`Seibang 0h, Elk Grove Village, 111.
`
`[73] Assignee:
`
`Littelfuse, Inc., Des Plaines, Ill.
`
`[21] Appl. No.: 868,421
`
`[22] Filed:
`
`Jun. 3, 1986
`
`Int. Cl.‘ ........... HOIH 85/24; HOlH 85/16
`[51]
`[52] US. Cl. .................................... 337/264; 337/264;
`337/255
`[58] Field of Search ............... 337/255, 256, 257, 258,
`337/260, 261, 262, 263, 264, 295
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`7/1983 Sian ..................................... 337/264
`4,394,638
`4,544,907 10/1985 Takano
`337/264
`
`4,604,602
`8/1986 Borzoni ............................... 337/264
`
`Attorney, Agent, or Firm—Russell E. Hattis; Stephen R.
`Arnold
`
`[57]
`
`ABSTRACT
`
`An automotive blade-type fuse has an enlarged trans-
`parent extraction flange. The flange is configured as a
`thin-wall structure having a cavity therein running sub-
`stantially its entire length. The fuse terminal blades are
`captively secured in a housing to extend from the bot-
`tom thereof and have narrow'extensions at the outer
`edges of the blades which extend upwardly into the
`flange cavity. A fuse link extends between the blade
`extensions within the cavity and at a stand-off distance
`from the interior walls of the cavity. The fuse housing is
`preferably of identical half-shell construction having
`lengthwise-running centering ribs and associated mat-
`ing recesses to facilitate assembly.
`
`Primary Examiner—Harold Broome
`
`21 Claims, 12 Drawing Figures
`
`
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 001
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 001
`
`

`

`U. S. Patent
`
`Jun. 2,1987
`
`Sheet 1 of 3
`
`4,670,729
`
`‘7=_z g_8_
`PRIOR ART
`
`
`
`n, Inc.
`Hunting Tita
`Ex. 1026
`Pg. 002
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 002
`
`

`

`U. S. Patent
`
`Jun. 2,1987
`
`Sheet2 of3
`
`4,670,729
`
`
`
`5:31——57.10..
`PRIOR ART
`
`all/l!
`
`
`
`
`
`I:
`
`
`
`
`E E
`
`72.1—99..
`PRIOR AR
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 003
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 003
`
`

`

`U. S. Patent
`
`Jun. 2,1987
`
`Sheet3 of3
`
`4,670,729
`
`
`
`25
`
`3|
`
`3"
`
`25' 713.2 g7- 12 _
`
`29
`
`29
`
`
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 004
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 004
`
`

`

`1
`
`ELECTRICAL FUSE
`
`DESCRIPTION
`
`1. TECHNICAL FIELD OF THE INVENTION
`The technical field of the invention is the electrical
`circuit breaker art, and in particular, automotive electri—
`cal fuses, although some aspects thereof have a broader
`application.
`2. BACKGROUND OF THE INVENTION
`Along with the increasing complexity and number of
`electrical circuits employed in automotive installations,
`there has grown an increasing demand for miniature
`fuses to protect these installations. Because of the num-
`ber of these fuses and the restricted available space to
`accommodate them, miniaturization of the fuses and
`their common fuse holder block has been a prime objec-
`tive.
`the currently favored automotive
`In particular,
`blade-type fuses are miniature fuses having a generally
`narrow housing body, from the bottom of which extend
`two coplanar parallel terminal blades. These fuses must
`meet certain standard test regulations of the Society of
`Automotive Engineers (SAE) and original equipment
`manufacturers (OEM) who specify the test conditions
`involved. The fuses must blow within certain minimum
`and maximum time limits under various test conditions.
`Thus, if a fuse blows in less than a given minimum time
`limit for the test condition involved, it is prone to pre-
`mature blowing and fails the test. It was discovered that
`even though these fuses have passed the various SAE
`tests, some prematurely blowing sometimes occurs
`under peculiar load conditions found in some automo—
`biles not specified so far in the test conditions. To avoid
`this premature blowing problem under these peculiar
`test conditions, the present unique “slow blow” fuse
`design was developed.
`The blowing time of a fuse is in part governed by its
`mass. The larger the mass for a given resistance, the
`longer its blowing time will be. The resistance of a fuse
`link increases with its length and decreases with the
`cross-sectional area. Thus, a fuse link of a given resis-
`tance has its maximum mass when the fuse link has a
`
`maximum length and thickness. Despite the fact that
`fuse engineers had knowledge of this fact, blade fuse
`designers have not designed their fuses to provide a
`desired maximum delay to minimize premature blowing
`problems which can arise under the peculiar load condi-
`tions referred to.
`
`In addition to accommodating a relatively massive
`fuse link, it is desired that fuse links should preferably be
`rigidly encased in an insulating housing which is suffi-,
`ciently rugged that there is negligible likelihood that
`upon fuse withdrawal a blade tears loose and remains in
`the fuse block. Removal of a broken blade under such
`conditions can be extremely tedious. Finally, it is desir-
`able that the fuse link itself be visible while the fuse is
`still in place in the fuse holder block, so that a blown
`fuse may be detected by rapid visual inspection of the
`entire aggregate of fuses.
`Two prior art patents exemplify bladetype fuses suit-
`able for automotive use embodying some, but not all of
`the abovementioned characteristics. Thus, US Pat.
`No. 3,909,767 issued to Williamson, et al. on Sept. 30,
`1975, illustrates the present commercially used automo-
`tive blade fuse. The structure will be discussed in fur-
`ther detail in the Description of Invention. The fuse
`design shown in this patent is still the most preferred
`
`5
`
`10
`
`15
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`20
`
`25
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`3O
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4,670,729
`
`2
`fuse design for most automotive circuits. In this type of
`structure, all metallic portions of the fuse are preferably
`formed as a single piece. This piece, except for exposed
`end portions of the terminal blades, is enclosed by an
`insulating fuse housing body preferably having a head
`portion provided with downwardly facing gripping
`shoulders to facilitate removal of the fuse from a fuse
`block. These shoulders have been provided by a flanged
`head. The fuse link extending between the terminal
`blades has generally been centrally disposed in the por-
`tion of the housing body below the flange portion
`thereof. The housing body is initially cold staked into
`staking apertures in the terminal blades and then the
`staked areas are ultrasonically welded, so that
`the
`staked portions of the housing more securely anchor the
`metal and housing portions together..
`The SAE specifications also include dimensional
`specifications which give the outer limitations of the
`dimensions of the fuse housing and terminal blades, so
`that automobile manufacturers can manufacture fuse
`holder blocks with fuse-receiving cavities which can
`accommodate the fuses. Therefore, while it may have
`been desirable to design the automobile fuses described
`with more massive fuse links to decrease the chances of
`
`premature blowing of the fuses, fuse designers could not
`increase the mass of the fuse to the desired ideal extent
`because of the space limitations in the fuse housing. The
`problem of fuse link size is particularly a problem in
`high current rated fuses where the fuse link requires a
`larger mass and must dissipate more heat than a lower
`current rated fuse. It is also more important in hotter
`higher current rated fuses to provide a significant space
`between the fuse link and the adjacent housing between
`walls to avoid damage to the housing. The space limita-
`tions in the housing of the prior fuse design did not
`provide the space necessary for a fuse link of the desired
`mass (i.e., the desired length and cross-sectional area) to
`overcome premature blowing problems and provide
`adequate spacing of the fuse link from the housing walls
`under the peculiar conditions referred to above.
`Another automotive blade fuse which was manufac-
`tured at one time and did not meet the electrical or
`dimensional SAE specifications is shown in US. Pat.
`No. 4,164,726 issued to Weibe on Aug. 14, 1979. In the
`fuse therein disclosed, the upper ends of the fuse blades
`extend with their full widths up into the head portion of
`the housing and the fuse link is attached thereto to ex-
`tend between the still closely spaced confronting mar-
`gins of the blade extensions. The effective electrical
`length and mass of the fuse link is determined by the
`close inter-blade spacing at the joint where the fuse link
`connects thereto and so this fuse link did not have the
`desired mass to avoid the premature blowing problem
`referred to. Moreover,
`this fuse link was physically
`embedded in the plastic of the fuse housing by injection
`molding and did not have the desired standoff distance
`between the fuse and the housing material. On the other
`hand,
`the housing was made transparent, so that a
`blown fuse element was readily visible in the head por-
`tion of the fuse.
`
`Both of the foregoing fuses are illustrated in the ac-
`companying drawings, and will be further discussed in
`the Description of the Invention.
`SUMMARY OF INVENTION
`
`The most preferred form of the invention is an auto-
`motive fuse provided with a pair of terminal blades
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 005
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 005
`
`

`

`4,670,729
`
`4
`FIG. 6 is a fragmentary side cross-sectional view of
`the upper portion of the assembled fuse, taken along
`section line 6—6 in FIG. 2.
`FIG. 7 is a sectional view of the fuse of the present
`invention, taken along section line 7—7 in FIG. 2, but
`prior to the ultrasonic welding of the housing body
`shells together.
`FIG. 8 is a perspective view of one form of prior art
`automotive fuse blade.
`
`FIG. 9 is a cross-sectional view of the prior art fuse of
`FIG. 8.
`
`FIG. 10 is a cross-sectional view of a second type of
`prior art fuse.
`FIG. 11 is an enlarged view of the portion of the fuse
`shown in FIG. 7 showing the engagement of alignment
`ribs during assembly.
`FIG. 12 is a fragmentary cross-section view along the
`section lines 12—12 in FIG. 2.
`
`DESCRIPTION OF THE INVENTION
`
`3
`extending from the bottom of a unique fuse housing
`body. The fuse housing body has a lower main body
`portion having a thin dimension that fits within the
`dimensional restrictions of the SAE dimension specifi-
`cations. A flanged portion of the housing projects above
`this main body portion in one and preferably both direc-
`tions forwardly and rearwardly of the main body por-
`tion to enclose a relatively large chamber or cavity
`which can accommodate an element of substantial
`length and cross-sectional area which cannot be accom-
`modated in the main body portion of the fuse. The
`flange portion when mounted in a fuse block of conven-
`tional design would be located above the fuse-receiving
`cavities therein which accommodate the narrow body
`portion of the fuse hdusing. The cavity in the flange
`portion of the fuse housing extends substantially the full
`length thereof. The upper ends of the fuse blades are cut
`away at the inner margins thereof to provide relatively
`narrow and widely spaced upwardly projecting fuse-
`carrying extensions which are located at opposite ends
`of this cavity. A fuse link of a length substantially
`greater than the interblade separation distance of the
`blades in the main body portion of the housing is at-
`tached to these widely spaced fuse-carrying extensions
`of the blades. The entire housing is made transparent if
`desired to render the fuse element readily visible at the
`top of the fuse housing.
`In accordance with another feature of the invention,
`the fuse housing is constructed in a different way than
`i
`, are the fuse housings of the previously designed blade
`fuses. The housing preferably comprises a pair of pref-
`erably identical shells placed closely around the blades
`and spaced from the attached fuse link and secured
`together along their confronting faces which are in a
`plane parallel to or coextensive with the plane of the
`fuse blades. The shell halves each preferably have lay-in
`f channels in which the blades are received, and guiding
`ribs and matching recesses for guiding the shells into
`wposition as they are assembled around the metal por-
`tions of the fuse. The shells further have pins which
`extend through apertures in the blades. The confronting
`faces of the peripheral housing portions are preferably
`ultrasonically welded together, as are the pins in their
`associated recesses in the shell bodies to form a secure
`assembly of the metal portions of the fuse and the fuse
`housing.
`invention discloses an easy-to-
`the present
`Thus,
`assemble miniature fuse which has a housing which can
`meet SAE size restrictions while enclosing relatively
`massive fuse links to minimize premature blowing prob-
`lems, and at the same time providing a desired spacing
`of the fuse link from the housing walls. Also it provides
`a secure retention of the fuse blades within the housing,
`and good visibility of the fuse link with the fuse in place.
`Other aspects and features of the invention will be-
`come apparent upon making reference to the specifica-
`tion, claims, and drawings to follow.
`DESCRIPTION OF THE DRAWINGS
`
`.
`
`FIG. 1 is an exploded perspective View of the princi-
`pal elements of the most preferred form of the fuse of
`the present invention prior to its assembly.
`FIG. 2 is a front elevation of the assembled fuse.
`FIG. 3 is a side View of the assembled fuse.
`FIG. 4 is a plan view of the assembled fuse.
`FIG. 5 is a front sectional view of the assembled fuse,
`taken along section line 5—5 in FIG. 4.
`
`10
`
`15
`
`20
`
`30
`
`35
`
`For purposes of convenience of description, the fuse
`will be described and claimed when it has a vertical
`orientation with the terminal blades projecting down-
`wardly from the bottom of the fuse housing. However,
`5 in actual use, the fuse can have other orientations.
`FIGS. 1—7 show the most preferred form of the fuse
`of the present invention. The fuse 10 consists of a fuse
`housing having a generally narrow main body portion
`12 surmounted by a generally rectangular flange por-
`tion 14. The main body portion 12 has closely spaced
`confronting front and rear walls 13A-13B formed by the
`lowermost sections of a pair of housing shells 15 and 17.
`Wide ribs 11 and 15 project from the central portions of
`the walls 13A and 13B. These ribs can serve as fuse
`orienting means in automatic fuse insertion equipment
`used by automobile manufacturers. The flange portion
`14 has from and rear walls 24,26 which are located in
`planes forwardly and rearwardly respectively of the
`walls 13A and 13B of the main housing portion 12 to
`form gripping shoulders 28,30 to aid in removal of the
`fuse from the fuse block. The end faces 16,18 of the
`flange portion 14 are in alignment with the correspond-
`ing end faces 20,22 (FIG. 2) of the main body portion
`12. In the preferred form of the invention, the flange
`portion 14 is symmetrically disposed with respect to the
`main body portion 12, but the broader aspects of the
`invention envisions asymmetric arrangements thereof.
`The flange portion 14 has a top wall 32 spanning the
`front wall 24 and the rear wall 26. The walls of the
`flange portion 14 define a sealed rectangular cavity 34.
`In the preferred embodiment of the invention the hous-
`ing is fabricated from a transparent synthetic thermo-
`plastic material allowing clear visibility of the interior
`of the cavity 34. A pair of strap-shaped planar blades
`36,38 are disposed in coplanar parallel alignment within
`the housing with their lower ends extending from the
`bottom thereof and their upper ends extending into the
`opposite ends of the cavity 34. The blades are provided
`with pairs of identically centered vertically spaced an-
`choring apertures 54—54, the confronting faces of the
`shells 15 and 17 having anchoring posts 23 extending
`into these apertures during assembly, as will be de-
`scribed.
`
`45
`
`50
`
`55
`
`60
`
`65
`
`The upper ends of the blades 36,38 have relatively
`narrow widely spaced extensions at the outer edges or
`margins thereof which project into the end portions of
`the cavity 34 where they are spaced from the walls of
`the flange portion 14 of the housing. Each of these
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 006
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 006
`
`

`

`4,670,729
`
`6
`tates assembly of the structure by providing a rapid and
`convenient alignment of the two housing shells 15,17.
`FIG. 7 shows in horizontal cross-section the structure
`
`5
`extensions 60,62 receives the ends of a fuse link 64. One
`particularly advantageous form of fuse link is formed by
`fabricating it from a piece of solder wire of appropriate
`specific heat, resistivity and melting point, and anchor-
`ing it within recesses in the blade extensions. To this end
`it is captively held between blade extensions 60,62 pref-
`erably configured as ferrule-forming extension Wraps of
`the blades 36,38 as shown in FIG. 1. Local heating at
`the ends of the fuse element then causes an immediate
`self-soldering operation of the fuse link 64 to the blade
`extensions 60,62.
`Considering next the assembly of the fuse, as indi~
`cated previously in the preferred form of the invention
`the fuse housing is formed of two identical prefabri-
`cated shells 15,17 made of a molded thermoplastic syn-
`thetic plastic material. Each forms one-half of the flange
`portion 14 and one-half of the main body portion 12.
`Each of the shells 15,17 has a pair of lengthwise running
`open-ended rectangular channels 19,21 dimensioned to
`closely accommodate in lay-in fashion the blades 36,38
`at both edges thereof. The metal portions of the fuse
`structure form a prefabricated sub-assembly as indi-
`cated in FIG. 1 with the fuse link 64 soldered to exten-
`sions 60,62 of the terminal blades 36,38 respectively, the
`blades being held in coplanar arrangement.
`Each of the shells 15,17 has a pair of outwardly ex-
`tending anchoring posts 23,23 on the inner surface, each
`located at a different opposite end of the associated
`blade lay-in channels 19,21. The apertures 54,54 in the
`blades 36,38 respectively are positioned so as to receive
`the posts 23,23 during assembly. Confrontingly dis-
`posed recesses 25,25 in each of the housing shells 15,17
`are so disposed that, when the two shells are subse-
`quently pressed and ultrasonically welded together,
`each post 23 enters its associated recess 25.
`Additionally, each shell is provided on its inner sur-
`face with an outwardly extending offset vertical guid-
`ing alignment rib 29 which projects outwardly further
`than the posts 23. Adjacent each rib is an insertion chan-
`nel or recess 31 of the same size and shape as the rib of
`the other shell to provide a friction fit therebetween.
`The longitudinal side faces 25’ of each rib 29 facing its
`adjacent channel (FIGS. 1 and 11) is an inclined exten-
`sion of the inner side Wall of the channel of the shell
`from which it extends and forms an outwardly tapering
`rib. The opposite side 25" of each rib is also inclined.
`The opposite ends 29',29' of each rib 29 are inclined to
`taper the longitudinal profile of each rib and the ends
`31’,31’ of the associated channel 31 are similarly shaped.
`Thus, when the two housing shells 15,17 are assembled
`and pressed together, a rib 29 from each housing half
`abuts the complementary side face 25’ of the other rib
`and these faces and the tapered ends 29’ of the ribs 29
`and the complimentary shaped surfaces of the channels
`31 into which the ribs 29 fit guide the shells 15,17 into
`proper alignment where the posts 23 enter and pass
`through the terminal blade apertures 25. Ultrasonic
`welding of the confronting faces of the shells 15,17, of
`the posts 23 and their associated recess walls and op-
`tionally of the ribs 29 and their associated channel walls
`provide a secure interconnection of all parts of the fuse.
`Further, it is believed that the above-described half-
`shell housing assembly is generally new in the art not
`only as applied to fuses, but also to other parallel-lead
`electrical components, such as capacitors, resistors, etc.
`In particular, it has been found that the use of alignment
`ribs 29,29 and matching channels 31,31 greatly facili-
`
`of FIG. 1 in assembled form and immediately prior to
`ultrasonic welding. It will be noted in particular that
`both blades 36,38 are not only anchored in position by
`the anchoring posts 23, but are also captively retained
`and positively aligned at the edges of their receiving
`channels 19 and 21, thereby imparting a significant de-
`gree of rigidity to the entire fuse structure.
`It will be seen from the foregoing that a relatively
`long and relatively massive fuse link 64 can be accom-
`modated by the fuse housing design and arrangement
`just described. The fuse link 64 spans a substantial entire
`length of the cavity 34 in the flange portion 14 of the
`housing. The effective electrical length and mass of a
`straight (or curved) fuse link between the widely spaced
`confronting surfaces of the blade extensions 60,62 is far
`greater
`than that of a corresponding straight
`(or
`curved) fuse link extending between the closely spaced
`inner margins of the portion of the blades in the main
`body portion 12 of the fuse housing. Also, the fuse ,link
`64 is substantially larger ‘in diameter than a fuse link
`which can be accommodated in any recess which could
`be formed in the thin main body portion 12, the thick-
`ness of which is limited by the SAE specifications
`which limit the size of the main body portion 12. The
`flange portion 14 is not so restricted because it will be
`above the automatic fuse-receiving cavities in the fuse
`holder which were designed to receive the old but still-
`to-be-used fuse version shown in FIG. 2 in circuits
`
`which do not pose a premature blowing problem.
`Thus, the fuse of the present invention is capable of
`accepting a fuse link having a length much longer than
`the main interblade spacing distance and a diameter
`much greater than any cavity which could be designed
`into the narrow main body portion 12 of the housing to
`provide a massive fuse link giving a slow but safe slow
`blowing property. Also, the fuse link is disposed in a
`transparent chamber at the top of the fuse body and
`which provides a desired stand-off distance between the
`fuse element and the housing walls. The fuse link being
`at the top of the fuse can readily be viewed with the fuse
`inserted into a fuse block. The fuse blades are not only
`secured by housing pins passing through apertures
`therein, but are sealingly secured and captively retained
`along their lengths in housing receiving channels.
`This is to be contrasted with the prior art structures
`shown in FIGS. 8-10. In discussing the structures, simi-
`lar part designation numbers will be used where appro-
`priate.
`FIGS. 8-9 show various views of the fuse illustrated
`in U.S. Pat. No. 3,907,767 and brieflydescribed in the
`Background of the Invention. This fuse is superior to
`the new fuse because it can be manufactured at a lower
`cost and because all metal portions thereof are formed
`as a single piece stamping from a string of fuse metal. In
`this fuse, the fuse link 64’ is shown formed as a inverted
`U-shaped portion integral with the fuse blades 36’,38’
`and occupying the wall space therebetween. The fuse
`link 64'
`is positioned within the central portion of a
`single housing piece 12’ where it cannot be as easily
`visually inspected for a blown condition with the fuse
`inserted into a typical deep fuse holder socket. Clearly,
`there is inadequate space between the blades to accom-
`modate a fuse of the length or diameter. of the fuse link
`64 shown in FIGS. 1—7. The housing 12' has an opening
`65 so it can be inserted over and around the blades.
`
`10
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`15
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`20
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`25
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`30
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`45
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`50
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`Hunting Titan, Inc.
`Ex. 1026
`Pg. 007
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 007
`
`

`

`4,670,729
`
`7
`Considering the cross-section of the assembled fuse as
`shown in FIG. 9, it will be seen that cutouts 76,78 in the
`upper ends of the fuse blades 36’,38' engage housing
`shoulders 72,74. The fuse blades 36’,38’ are secured by
`staking and ultrasonically welding the housing into fuse 5
`blade apertures 54'. A stand-off distance is provided
`between the fuse link 64’ and the closely spaced walls of
`the housing 12’. The close spacing of the fuse blades and
`the thickness of the housing obviously do not provide
`space for a massive fuse link like fuse link 64’ in the fuse to
`of FIGS. 1-7.
`FIG. 10 shows the fuse described in U.S. Pat. No.
`4,164,726, also briefly described in the Background of
`the Invention. Here a fuse link 64” is affixed to the ends
`of fuse blades 36",38” by clip-like structures. The blade 15
`and link assembly 36",38”,64” is held in position while a
`housing consisting of a body 12 and an integral flange
`14” is formed around this assembly by injection mold-
`ing. As in the present invention, the fuse link 64" is
`disposed within the flange portion 14” of the housing 20
`12”. Further, the housing may be made transparent to
`allow easy visual inspection of a blown fuse. However,
`the flange portion of this housing is not located above a
`main body portion which fits within the fuse block
`cavity of fuse blocks. Rather it is positioned to fit within 25
`such cavities when these cavities were designed to pro—
`vide appreciable clearance, since the flange size exceeds
`the SAE size limitation specifications. Also, the flange
`of the fuse is much smaller than the flange of the com-
`mercial fuse of the present invention. Furthermore, the 30
`fuse link 64" is closely encased by the housing material
`molded around it, so that case rupture can readily occur
`‘ during a short-circuit blowout. Of most significance is
`that the fuse length is inefficiently utilized, since it is in
`electrical contact with closely spaced portions of the 35
`blades 36”,38” so that its effective resistance and mass is
`only that part of the fuse link which is between the close
`7 margins of the blades. The fuse of US. Pat. No.
`' 4,164,726 thus does not disclose one of the features of
`the present invention where the fuse link extends be- 40
`“tween narrow upstanding blade extensions like 60,62
`(FIGS. 1—7) at the outer edges of the blades.
`While the invention has been described with refer-
`
`ence to a preferred embodiment, it will be understood
`by those skilled in the art that various changes may be 45
`made and equivalents may be substituted for elements
`thereof without departing from the broader aspects of
`the invention. Also, it is intended that broad claims not
`specifying details of a particular embodiment disclosed
`herein as the best mode contemplated for carrying out 50
`the invention should not be limited to such details. Fur-
`thermore, while, generally, specific claimed details of
`the invention constitute important specific aspects of
`the invention, in appropriate instances even the specific
`claims involved should be construed in light of the 55
`doctrine of equivalents.
`I claim:
`
`1. An electrical fuse comprising:
`an electrically insulating fuse housing including a
`main body portion having closely spaced generally 60
`parallel confronting major front and rear body
`walls and a flange portion at the top margins of said
`main body portion and extending generally upward
`therefrom, said flange portion including major
`front and rear flange walls, at least one of said 65
`major front and rear walls being disposed out-
`wardly offset from its corresponding front or rear
`body wall, said flange portion having a cavity
`
`8
`therein defined by interior wall surfaces of said
`flange portion;
`a pair of conducting fuse terminals configured as
`generally strap-shaped blades disposed parallel and
`coplanarly so as to have parallel confronting proxi-
`mal blade edges and mounted within said housing
`parallel to said front and rear body walls with said
`blades extending from a bottom portion of said
`housing, the upper ends of said blades having rela-
`tively narrow upward extensions only at the outer
`margins thereof which narrow extensions are lo-
`cated at the opposite ends of said cavity; and
`an elongated meltable fuse element
`in said cavity
`extending between and affixed to said narrow blade
`extension of said terminal blades and spaced away
`from said interior wall surfaces, the distance be-
`tween the inner surfaces of said front and rear
`flange walls exceeding the maximum distance be-
`tween the exterior surfaces of said front and rear
`
`body walls, at least a portion of said flange portion
`being sufficiently transparent to allow visual in-
`spection of said fuse element.
`2. An electrical fuse comprising:
`an electrically insulating fuse housing having closely
`spaced generally parallel confronting major front
`and rear body walls;
`a pair of conducting fuse terminals configured as
`generally strap-shaped blades disposed parallel and
`coplanarly so as to have parallel confronting proxi-
`mal blade edges and mounted within said housing
`parallel to said front and rear body walls with said
`blades extending from a bottom portion of said
`housing, the upper ends of said blades having rela-
`tively narrow upward extensions only at the outer
`margins thereof; and
`an elongated meltable fuse element extending~ be-
`tween and affixed to said narrow blade extensions
`of said terminal blades.
`
`3. An electrical fuse comprising:
`an electrically insulating housing having closely
`spaced generally parallel spaced confronting front
`and rear body walls;
`a pair of adjacent parallel conducting fuse terminals
`secured within said housing parallel to said front
`and rear housing walls so that lower ends of said
`terminals extend from a bottom portion of said
`housing, said terminals being configured as gener-
`ally strap-shaped blades disposed parallel and co-
`planarly so as to have parallel confronting proxi-
`mal blade edges and parallel distal blade edges, said
`upper ends of said fuse terminal blades being con-
`figured with narrow upward extensions extending
`from said distal edges; and an elongated fuse ele-
`ment having two ends, each end being affixed to a
`different one of said extension portions.
`4. An electrical fuse comprising:
`an electrically insulating housing including a main
`body portion having a size to fit within the maxi-
`mum permitted space requirement of a set of hous-
`ing and blade size specifications, said main body
`portion having closely spaced generally parallel
`confronting major front and rear body walls and a
`flange portion at the top of said main body portion
`to be located beyond the space to be occupied by a
`body portion having said maximum permitted size
`specification, said flange portion including major
`front and rear flange walls, at least one of said
`major flange walls being disposed offset outward
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 008
`
`Hunting Titan, Inc.
`Ex. 1026
`Pg. 008
`
`

`

`4,670,729
`
`9
`of the corresponding front or rear body wall, said
`flange portion having a cavity therein formed by
`interior wall surfaces of said flange portion;
`a pair of parallel conducting fuse terminals mounted
`within said housing parallel to said front and rear
`body walls so that lower ends of said terminals
`extend from a bottom portion of said main body
`portion and so that upper ends of said terminals
`extend into said cavity; and
`a fuse element extending between the upper ends of
`said fuse terminals so as to be supported within said
`cavity and spaced from said interior wall surfaces
`of said flange portion.
`5. The fuse of claim 4 wherein said fuse terminals are
`configured as generally strap-shaped blades and are
`disposed parallel and coplanarly so as to have parallel
`confronting proximal blade edges and parallel distal
`blade edges.
`6. The fuse of claim 5 wherein said upper ends of said
`fuse terminal blades have narrow extension portions
`projecting upward from said distal edges, so that their
`confronting margins are spaced apart a much greater
`distance than the confronting margins of the terminal
`blades therebelow, said fuse element extending between
`said narrow extensions.
`7. The fuse of claim 1 or 4 wherein the distance be-
`tween the inner surfaces of said front and rear flange
`walls exceeds the maximum distance between the exte-
`rior surfaces of said front and rear body walls.
`8. The fuse of claim 1 or 4 wherein each of said major
`flange walls is offset outwardly from its corresponding
`body wall.
`‘
`9. The fuse of claims 1, 2, 3 or 4 wherein said housing
`is initially fabricated as a pair of front and rear shell
`halves subsequently secured together about said fuse
`element and said fuse terminals.
`10. The fuse of claim 1 or 4 wherein at least a portion
`of said flange portion is sufficiently transparent to allow
`visual inspection of said fuse element.
`11. In an electrical device having a pair of spaced
`parallel confronting coplanar strap-shaped terminal
`blades connected to an electric circuit element extend-
`ing between confronting ends of said blades and a rigid
`insulating housing enclosing said terminal blades, the
`improvement comprising:
`a pair of housing shells configured to enclose said
`blades and