Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to fuses and in particular to an
electrical cut-out deYice.
Blectrical cut-out devices are used to provide fusible
connections in high voltage power lines in order to break the electrical
connection between a pair of power lines when an overload occurs.
Typically, the cut-out devices are veItically mounted to a utility pole and
comprise an insulator electrically isolating upper and lower terminal
assemblies receiving the power lines. A cylindrical fuse carrier having an
arc quenching liner houses a fuse element and extends between the terminals
in parallel with the insulator. A pivotal connection for the fuse carrier is
usually provided in the lower terminal assembly and typically is in the form
of a shallow downwardly extending slot to allow the fuse calrier to be
engaged releasably to the lower terminal assembly. The fuse carrier, when
positioned in the slot, can ~hen be swung upwards to engage with the upper
terminal assembly, thereby fiorming an electrical connection between the
power lines.
When a current overload occurs, the fuse element and the arc
quenching liner vapoAze to break the electncal connestion between the upper
and lower terminal assembIies. The vapo~ized element and liner create a
large internal pressure in ~he fuse carrier and are forced out of the lower end
of the fuse carner.
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However, since ~he lin~r and fuse element vapour are
discharged downwardly, the possibility of injuring a passerby or damaging
equipment loca~ed beneath the cut-out dsvice is of soncern. Also, since the
fuse carrier is seated in a shallow slot, the fuse carri~r may disengage from
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the slot when the fuse carrier disengages from the upper terminal assembly
and swings downwardly after an overload occurs.
The horizontal mounting of cut-out devices has been
S considered. In particular, IJ.S. patent 2,113,632 to Steinmayer shows a
horizontally mounted, low voltage cut-out device including a ~use carrier
connec~ed across a pair of terminal assemblies. To facilitate the connection,
one of the terminals is provided wish a horizontal slot having a pair of
upwardly extending hooks fonning an open outer end. The outer end of the
slot receives the filse carrier allowing it to be slid towards the terminating
end of the slot and pivoted so that the other end of the fuse carrier can be
bolted to the other terminal assembly in order to complete the circuit
between the power lines.
However, a proWem exists in that the filse carrier is not easily
disengaged from the other terminal assembly and thus, the time required to
replace the fuse element housed in the fuse earrier is increased. Another
problem exists in the Steinmeyer device in ~at although the provision of the
honzontal slot pe~nits the fuse carrier to slide longitudinally along the slot,
the user is required to bias the fuse carrier against the terminating end of thehorizon~al slot when pivoting the fuse carrier in order to connect the other
end of the fuse carrier with ~he other terrninal assembly. Thus, the slot
fails to aid in posi~ioning the ~use carrier when pivoting for engagemen~
across the terminal assemblies and to locate the fuse carrier securely to
2S withstand ~e for~ imposed in service. Moreover, another problem exists
in that ~he Steinmayer device c~not be re-fused wlth the power lines
energiæd. Accordingb, ~ere is a need ~or an improved electrical cut-out
device.
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It is therefore an object of the pres~nt invention to obviate or
mitigate the above disadvantages.
According to one aspect of the present invention there is
provided an electrical cut-out dsvice for electrically connecting a pair of
power lines interconnected by a substantially horizontally mounted insulator
cornprising:
a pair of conductive terminals each for receiving one o~ said
power lines, each of said terminals including securing means on one end
thereof, said securing means securing each of said terminals to one end of
said insulator so that said terminals extend downwardly therefrom to define
outwardly and inwardly facing sides, one of said terminals having a
passageway formed therein having an o~en end in the outwardly facing side
~reof, said passageway extending steeply downwards from said open end
when said one terminal is extending downwardly ~rom said insulator, said
passageway being shap~d at the other end thereof to define a bearing surface;
releasable latch means located on the other of said terminals;
and
a ~usible link connectaUe in a substantially horiz~ntal
operative position between said one and other terminals to connect
elec~ically said tem~inals, one end of said filsible link including means for
slidably engaging in said passageway when said means is aligned with said
open end, said fi~ le link being pivotal in said passagew~y when said means
is positioned at the othe~ end of said passageway to engage releasably 1he
other end of said fusible link with said latch means.
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According to another aspect of the present invention there is
provided a generally horizontally mounted electrical cut-out device
comprising:
an insulator for interconnecting a pair of power lines;
S a pair of conductive terminals each for receiving one of said
power lines, each of said terminals extending downwardly from one end of
said insulator and defining outwardly and inwardly facing sides, one of said
terminals having a steep, downwardly extending passageway formed the~ein,
said passageway including an open end formed in the outwardly facing side
and being shaped at the other end there~>f to define a bearing surface;
releasable latch means located on the other said terminals; and
a fusible link connectable in a substantlally hori~ontal
operative position between said terminals to connect electrically said
terminals and one of said fusible link including means for slidable engaging
in said passageway when said means is aligned with said open end, said
fusible link being pivotal in said passageway when said means is positioned
at the other end of said passageway ~o engage releasably the other end of
said fusible link with said latch means.
Preferably, ~e passageway is steeply angled relative to the
longitudinal a~cis of the ~usible link to prov;de an abutment surface to inhibitlongitudinal movement of the fusible link when it is connected across the
terminals. The provision of the steeply angled passageway also provides a
bias for ~e filsible link perpendicular to the longitudinal ~xis of the fosible
link to maintain the fusible linlc in the passageway when the fusible link is
disengaged from ~he latch means. Furthe~more, it is also preferred th~t the
fusible link is pro~ided wi~ a cam surface at the one end and the one
tenninal is provided with a~resilient Tetainer such ~at upon pivotal
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movement of the fusible link to engage the other end of the filsible link with
the latch means, the one end of the fusible link contacts the resilient retainerand is biased in a direction along the axis of the fusible link towards the
latch means.
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These features allow the present device to be mounted
horizontally on a utility pole or positioned in an in-l;ne condition to increasesafety in the event of an arc quenching liner and fuse element vapour
discharge while facili~ating the removal and engagement of the filsible link
across the electrically isolated terminals.
Embodiments of the present invention will now be described
more fully with reference to the accompanying drawings in which:
Figure 1 is a side view of an elect~ical cut-out device;
Figure 2 is an enlarged side view par~y in section of a portion
of the device illustrated in Figure l;
Figure 3 is an enlarged side view partly in section of another
portion of the device illustrated in Figure l;
Figure 4 is ar~ enla~ged rear view of the portion illust~at~d in
Figure 3;
Figure S is another enlarged side view l?artly in section of the
po~on illustrated in ~igure 3;
Figur~ 6 is a side view OI t}~e device shown in Figure 1 in an
in-line condition; and
l~igure 7 is a partial perspective view of the device shown in
Figure 1 in a pole mount condition.
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Referring to the Pigures, an electAcal cut-out device 10 is
shown interconnecting a pair of power lines 12 and 14. The cut-out device
10 includes a pair of terminal assemblies 16 and 18 receiving the power lines
12 and 14. The terminal assemblies are mounted on opposite ends of an
S insulator 20 which electrically isolates the power lines 12 and 14. A fuse
assembly 22 extends between the terminal assemblies 16 and 18 to complete
the electrical circuit between the two power lines 12 and 14 while
functioning to interrupt the electrical circuit in the event of a current
ov~rload.
The terminal assemblies 16 and 18 include aluminum brackets
24 and 26 secured at one end to opposite ends of the insulator 20 and
projecting downwardly sufficiently from the insulator 20 to provide clearance
between the fuse assembly 22 and the insulator 2û.
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The brac~cets 24 and 26 are secured to the lnsulat~r 20 by
"U"-shaped bolts 28 and 30 and have curved lower surfaces 32 and 34
respectively, each lower surface being prwided with a tapped bore. The
lower surface 32 is secured to the mating top surface 35 of a bifurcated
coupling 36 ~ormed from co~per via a bolt 37 which threadably engages with
the bore. The coupling 36 is tin coated in suitable areas ~o prsclude ths
galvanic ~eaction between the copper coupling and the aluminum bracket.
The couRling 36 includes a pair of spaced side walls 36a, 36b and outwardly
and inwa~dly facing sides 36g, 36h respectively. The interior surfaces of the
side walls 36a and 36b are each p~ovide~ with a curved passageway 38a and
38b re~ec~ively, in the form of a channel with each passageway having an
o~ening near ~e upper po~on of the coupling 36 in the outwardly facing
side 36g of ~e coupling 36. Ihe passageways 38a,3gb serve to receive one
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end of the fuse assembly 22 and are sufflciently deep to inhibit accidental
disengagement with the fuse assembly.
The curved passageways 38a and 38b are inwardly and steeply
S angled with respect to a horizontal axis and terminate in substantially ver~c~
poItions 40a and 40b positioned on the~ longitudinal axis of the coupling 36.
The vertical portions 40a and 4ûb are of sufflcient depth to provide bearing
surfaces 42a and 42b for facili~ating rotation of the ~use assembly 22 and to
provide abutment surfaces 44a and 44b for preventing movement of the fuse
assembly 22 along its longitudinal axis when engaged aeross the two terminal
assemUies 16 and 18. A curved resilient retainer 46 is secured at one end to
the coupling 36 by the bolt 37 and is positioned between the two sides 36a
and 36b of the coupling 36. This provides additional support to p~event
movPment of the fuse assembly 22 along its longitudinal axis when engaged
between the terminal assemblies in an operative position and forms an
auxiliary electrical contact between the terminal assembly 16 and the fuse
assembly 22. A securing plate 48 is removeably secured to one side of the
coupling 36 by a nut and bolt 50 to allow the power line 12 to be pinned
between the plate 48 and the coupling 36.
A copper latch housing is secured to t~e bracket 26 by a bolt
51 thr~adably engaged with the ~apped bore so tha~ the top surface 52 of the
housing mates with the curv~d lower surface 34 of ~e bracket. The latch
housing is also tin coated in suitable areas. The housing 54 has a pair of
sidewalls 54a and 54b and a backwall 54c and supports the female portion 56
of a latch 58. The latch 58 ineludes a pair of curved resi1ien~ plates 60 and
62. The p~ate ~ is secured to a support 64 locate~ in the housing 54 by a
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nut and bolt 66 and is biased towards and positioned to provide an abutment
surface 68 capable of being displaced upwardly against the bias.
The other resilient plate 62 is secured at one end to the
S backwall 54c by a connector 70 and is positioned below the plate 60. The
plate 62 is suppor~d along a portion of its length by a support 72. The
other end 74 of the plate 62 is disposed adjacent the plate 60 and is capable
of being displaced towards the backwalll 54c agains~ the bias. The abutment
surface 68 and the other end 74 are separated to pro~ide an aperture 76 for
receiving the male poItion 78 of the latch 58 located on the fuse assembly
22. A second secunng plate 80 is removeably secured to the sidewall 54a
by a nut and bolt 82 to allow the power .line 14 to be pinned between the
plate 80 and the housing 54.
The fu~e assembly 22 comprises a cylindrical fuse carrier 84
having an inner arc quenching liner and is connected at one end 84a to a
bifurcated connector 86. The connector 86 includes a pair hooked
extensions 88 and 90 shaped to fonn a c~n surface 92 for co operation with
the coupling 36 in a manner to be descnbed here;n.
: ~ The sides of the connector 86 are provided with outwardly
e3ctending trunnions 94a and 94b. The trunnions 94a and 94b a~e positioned
and dimensioned to engage slidably in the passageways 38a and 38b and to
form a pivotal connechon between the ~use assembly 22 and the coupling 36.
Crossbars 96 and 98 int~rconnect the extensions 88 and 90. The ~ro~sbar 96
engages with the resilient retainer 46 when the fuse assembly 22 is pivoted
in the coupling 36 to engage the fuse assembly 2~ with the terminal
~ assembly 18.
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The connector 86 is secured by a pivot pin to a bracket 10
formed on the fuse calTier 84 to define a hinge 100. The bracket 102
encircles the fuse carrier 84 and is secured thereto by a suitable fastener
104. l~e bracket 102 also includes a lif~ing ring 106 to ~aciLita~e removal
and the pla ement of the fuse assembly from or on the coupling 36. The
connect~r 86 terminates at its lower end to form an abutment member 110
which abuts against the open end 84a of the fuse carrier 84 when the fuse
assembly is in an operative position. The hinge 100 is biased by a spring
(not shown) in a direction to force the abutment member 110 away from the
fuse carrier 84 when the memb~r 110 ls not restrained by a fuselink.
A male portion 78 of the latch 58 is secured to the other end
84b of the fuse carrier 84. The male portion 78 includes a housing 112
receiving the fuse carrier 84 and is secured to the carrier 84 by a suitable
f stener 114. One end of the housing 112 is provided with threads to
receiYe an end cap 116 which sea1s one end o~ the fuse carrie~ 84. A post
118 extends upwardly from the housing 112, the up~er surface of which
defines an sngagement plate 120. The plate 120 is at a slight angle to the
horizontal and is dimensioned to extend outwardly beyond the sides of ~e
post 118, thereby exposing a portion of its undersu~face. The engagement
plate 120 is also of a thickness greater than the separ~tion distance or
aperture 76 formed between the two plates 60 and 62.
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The male portion 78 also insludes an arm 122 pivotally
connected to the post 118 by a hinge pin 124. The arm 122 tenninate3 at
one end in a pull nng 126 which is position~d below the fuse carIier 84 to
facilitate access. The o~ end 128 af ~e arm 122 extends upwardly along
side the post 118 and is bias~ thereagainst by a spring (not shown).
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A third securing plate 130 is removeably held against the
abutment member 110 by a bolt 132 to allow one end of a fuse cable 134 to
be sscurgd to the connector 86. The iùse cable 134 as is well known in the
art, extends into the fuse carrier 84 and is coupled to one end of a fuse
S element (not shown). TSle other end of the fuse element extends through the
~use carrier 84 to the other end thereo~F. The fuse element is held in
electrical contact with the male po~tiosl 78 of the la~ch 58 by the end cap
116. The connection of the fuse cable 134 to the member 110 at one end
and to the end cap 116 at ~e other end counters the bias of the hinge 100
which acts to force the abutment member 110 away from the fuse car~ier.
Thus, the fuse cable 134 when intact maintains the abutment member 110
against the open end 84a of the fuse carrier.
The connec~ion and operation of the cut-out device 10 will
now be described. ~irstly, the terminal assemblies 16 and 18 of the cut-out
deYice 10 are secured to either ends of the insulator 20 so that they depend
there3From. The power lines 12 and 14 are then secured to the Iespective
~elminal assemblies 16 and 18 by the securing plates 48 and 80. Prior to
connecting the fuse car~ier and fuss cable across the terminal assemblies 16
and 18, the end cap 116 is removed from the housing 112. The fuse element
and fue cable 134 are in~ted into fuse ~er 84 so that the fuse cable
extends beyond ehe open one end 84a and the fuse element abuts againæt the
other end 84b of the fuse carrier 84. The end cap 116 is then threadably
engaged with the housing 112 to secure ~e fuse element and cable 134 in the
. ~ 25 fuse car~ier. The end of ~he filse cable 134 extending fr~m the open end 84a
of the carner is then pmned to the abutment member 110 by the s~curing
plate 130 which acts against the bias of the hinge 100 to hold the open end
84a against ~e member 110.
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With this complete, the fuse assembly 22 is held via the lifting
sing 106. The lifting ring 106 is positioned relative to the centre of gravity
of the fuse assembly 22 so that the fuse assembly 22 assumes a substantially
vertical orientation. With the fuse assembly in this orientation, the assembly
is positioned to bring the trunnions 94a a~nd 94b into alignment with the open
end of the passageways 38a and 38b provided in the outwardly facing side
36g of the coupling 36. With the trumnions aligned, the fuse assembly 22 is
slid downwardly so that the tmnnions 94a and 94b move along the
passageways until they rest at the bottom of the passageways in the vertical
sections.
The cam surface 92 defined by the extensions 88 and 90
allows the connector 86 to engage with the coupling 36 without eontacting
the retainer 46 whilst perrnitting the crossbar 96 to contact the retainer 46
when tlle fuse assembly 22 is in a substantially horizontal orientation.
Moreover, the design of the extensions 88,90 and the passageways 38a,3~b
only permits the trunnions 94a,94b to slide to the bottom of the passageways
when the fuse assembly 22 is in a substantially vertical orientation. This
prevents the fuse assembly 22 from mal~ng an electrical connection between
the two terminal assemblies 16 and 18 when the fuse assembly 22 is not
seated properly in the passageways.
When the trunnions 94a and 94b are seated at the bottom of
the passageways, ~e fuse assembly 22 is swung upwardly. The depth of the
vertical sections 40a and 40b provide ~ing surf~ces 42a and 42b and
fa~ilitate the piYoting motion of the fuse assembly 22 by maintaining the
position of the trunnions in the passageways. When fuse assembly 22 is
swung upwardly, the outer edge the engagement plate 120 abuts against the
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other end 74 of the resilient plate 62 forcing it to move laterally into the
housing 54 against the bias. VYhen this occurs, the engagement plate 120 is
capable of further upward movement, thereby allowing the top surface of the
plate 120 to abut against the abutment surface 68 of the plate 60 causing its
displacement upwardly against the bias.
After the plate 60 has been displaced upwardly by a distance
sufflcient to form an ap~rture 76 betwoen the plates 60 and 62 larger in size
than the plate 120, the outer ed~e of ~he engagement plate 120 no longer
biases the resili~nt plate 62 into the housing. This allows the resilient plate
62 to spring back towards the post 118 beneath the plate 120. When the
upward force impos~d on the fuse assembly 22 subsides, the plate 60 forces
the engagement plate 120 towards the lower plate 62. This action results in
the plate 120 being held between the plate 62 and the surface 68 thereby
securing the male portion 78 to the female por~on 56 and completing an
elec~ical connection between the power lines 12 and 14 via the assemblies
16, 22 and 18.
To release the connection between the resilient plates 60 and
62 and the engagement plate 120, the pull ring 126 is pulled downward
thereby pivoting the ann 120 via hinge 124. The pivo~ng action forces the
o~er end 128 of the arm 120 to abu~ against ~ resilient platc 62 causing it
to move laterally into the housing ~4. When ~he other end 128 of the ~rm
has moved the plate 62 beyond the outer edge of the engagement plate 120,
the filse assembly :22 is released ~rom the housing 54. With the filse
assembly released ~om the terminal assembly 18, ~e assembly 22 swings
: downwardly under the influence of gravit~ vh its pivotal connection with the
terminal assembly 16. In this position, the fuse assembly 22 can be
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disengaged from the coupling 36 by engaging the lifting ring 106 and sliding
the trunnions 94a and 94b upwardly through the passageways.
When the cut-out device 10 is connected across the power
S lines and an overload occurs, the arc quenching liner and the fuse element
vaporize and due to the increase in pressure within the fuse carner 84 are
jettisoned outwardly through the open end 84a of the ~use carrier in the case
of a low fault overload and outwardly through both ends in the event of a
high fault overload if the internal pressure attained in the fuse carrier is
sufflcient to blow out the end cap 116~
When the fuse element vapourizes, the tension in the fuse
cable 134 is released. This allows the spring to force the abutment member
110 away from the end of the fuse carrier 84 via the hinge 100. As the
member 110 and fuse caener are forced apart, since the trunnions 94a,94b
remain seated in the bottom of the passageways 38a,38b, the connector 86
pivots within the passageways via the tmnnions which in turn swings the
hinge 100 in an arc away from the terminal assembly 18.
The movement of the hinge 100 in this manner forces ~e plate
120 to slide relative to the two plates 60 and 62 and out of the aper~ure 76.
-~ When the plate 120 slides a sufflcient distance to clear the plate 62, the fuse
assembly 22 becomes disengaged from the terminal assembly 18 and is free
to swing downwardly via the pivotal connection with terminal assembly 16
under the in~uence of gravity. Since the passageways 38a,38b are
sufficiently deep, there is lit~e or no chance of the fuse assembly 22
accidentally disengaging from~the termin21 assembly 16 as it swings.
Accordingly, since ~e fuse assembly 22 ~rees itself from the terminal
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assembly 18 when an overload occurs, the device 10 gives a vi~ual indication
of the occurrence of a fault.
Referring now to Figures 6 and 7, the present cut-out device
S 10 is shown in an in-line condition ancl in a pole mount condition. In the in-
line conditicn illustrated in l~igure 6, tlhe device 10 interconnects the p~wer
lines 12 and 14 as the lines span be~veen suitable utili~ SUppOItS. Howe~sr,
as can be seen in Figure 7, the device 10 can also be mounted to a utility
pole 200. When the device 10 is to be mounted in this fashion, a bracket
202 is secured to the insulator 20 via a "U"- bolt 2W. A mounting post 206
bolted to the utility pole extends ~rom the pole 200 and is bolted to the
bracket 202. A power line 20$ is connected to the terminal assembly 16 in
the manner described ab~ve and extends to a consumer location or
transforrner. A second power line 210 extends from the te~minal assembly
18 to the overhead power lines. Thus, as can be seen ~e present de~ice is
capable of operating in various environments.
The pressnt device provides advantages in that since the cut-
out device 10 is mounted in a substantially honzontal position with respect to
~he ground, vapour is jettisoned from the ~use carrier 84 in a direction that
precludes the possibility of damage to equipment or injury to a passerby.
Also, since the passageways 38a and 313b are sufflciently deep and steeply
angied downwardly, the trurmions 94a and 94b ale maintained in position in
the passageways when the fuse assembly swings downwardly after releasing
from the terminal assembly 18. Purthermore, ~he abutment surfases 44a and
44b provide additional support for the ~unnions 94a,94b to inhibit m~vement
of the fuse assembly 22 along its~ axis when in an operating posi~on.
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