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Патент USA US2109090

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Feb. 22, 1938.
R. R. PITTMAN ET AL
2,109,090
HIGH DUTY FUSE SWITCH
Filed Jan. 1e, 1957
I
a sheets-sheet 1
2
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Fzy. 2
vENToR
ATTORN EY
Feb. 22, 1938.
R. R, plTTMAN ET AL
2,109,090
HIGH DUTY FUSE SWITCH
Filed Jan. 16, 1937
2 Sheets-Sheet 2
F257. 6
INVENTOR
ATTOR N EY
2,109,090
Patented Feb. 22, 1938
lUNITED STATES PATENT OFFICE
2,109,090
,
HIGH DUTY FUSE SWITCH
Ralph R. Pittman and Carroll H. Walsh, Pine
Bluif, Ark.
Application January 16, 1937, Serial No. 120,962
17 Claims.
'I’his invention relates generally to fuse switches
Y used for the purpose of protecting high tension
electrical circuits against excessive over currents,
and particularly to the type of fuse switch known
Ul in this art as “dropout” switches, i. e., a com
bined switch and fuse in which thefuse cartridge
of the device is actuated to the open switch posi
tion in response to the rupture of a fusible ele
ment. Switches of this type are not new in this
10 art; one of the first being disclosed in a patent
dated Nov. 15, 1910, No. 975,431, issued to R. P.
Jackson.
.
i
The present invention has for its principal ob
ject an improved structure for the purpose of
i Ol providing a fuse switch of this general type hav
ing relatively high power interrupting ability in
comparison to prior art structures, through the
provision of means for controlling and expanding
(Cl. 2004114)
Fig. 3 is a plan view of the upper end of the
fuse cartridge of the device.
Fig. 4 is an enlarged fragmentary sectional ele
vation of the upper end of the fuse cartridge.
Fig. 5 is a fragmentary front view of the ex
haust vent or opening at the upper end of the
cartridge.
'
Fig. 6 is a plan view, as seen from below, of
the upper terminal member.
By reference to Fig. 1, we will first describe the 10
fuse cartridge mounting, which includes the
metal base I0, the spaced insulators II and I2
suitably mounted thereon, and the upper and
lower conducting terminal members I6 and 46,
which are respectively secured to the upper and 15
lower insulators by means of the bolts I3 and 45.
For convenience in connecting the device in a
circuit, the line terminal I4 is arranged in posi
tive electrical contact with the upper terminal
the gases generated under high pressures inci
member I6, and is provided with a nut I5 for 20
2 O dent to such duty.
'
engaging
a line wire; similarly, the load terminal
More speciñcally, among the objects of the
43
is
arranged
in positive electrical contact with
present-invention may be noted (1) means re
sponsive to the blowing of a fuse link within the the lower terminal member 46, and is provided
cartridge of the device for closing a vent at the with the nut 44 for engaging a load wire.
The upper terminal member I6, as shown-in 25
25 upper end of the cartridge and removing a clo
sure from the lower end, and at the same time
releasing the cartridge from the closed switch
position; (2) the arrangement for relieving the
high pressures within the cartridge due to the
30 interruption of relatively large currents at two
points and in such a manner that the recoil
will maintain the switch in the closed position
until the gas‘pressure has been greatly reduced;
(3) the provision of means for progressively clos
35 ing a vent atA the upper end of the cartridge and
at the same time progressively increasing the vol
ume of the hollow within the cartridge to avoid
impact;_ (4) the provision of resilient means for
absorbing the initial impact due to the inter
40 ruption of heavy current by permitting an up
ward travel of the cartridge, together with means
.for limiting the extent of such travel; (5) an
arrangement of vents such that, under normal
4
conditions, the entrance of rain or insects are
excluded from the cartridge, but which exhaust
the gases under- conditions of operation in such
a“ manner and direction as to prevent short cir
cuits due to gaseous conducting iiame and (6) a
5 O. new, simple and effective fuse switch having rela
tively great interrupting ability.
Withthese and other objects in view as may
later appear, our invention resides in the novel
form of the elements making up the device, and
55 their arrangement and combination.
In the drawings (2 sheets):
Fig. 1 is a side elevational view of the device,
shown partly in section.
^
Fig. 2 is a sectional view 0f the device, taken
60 -along the line II-II in Fig. 1.
Figs. 1 and 6, comprises the channel-shaped for
wardly extending portion which serves as a
weather shed for the upper parts of the device.
The upper terminal member contact I'I is sup
ported between the vertical channel walls on the 30
pivot 20, and extends forwardly therefrom along
and within the channel section. Intermediate of
its ends, the upper terminal member contact is
provided with a cylindrical recess I 9, between the
bottom of which and the upper inner surface of 35
the channel member is interposed the spring I8;
the latter continually biasing the upper terminal
contact member I‘I. in a clockwise direction about
the pivot 20. Forwardly from the recess I9, the
upper terminal contact member I1 is provided 40
with an inwardly and upwardly arcuate surface,
beyond which it is upwardly sloped to its end.
To prevent damage to-the spring I8 and/or the
pivot 20 due to thermal eiîects of electrical cur
rent therethrough, the upper terminal contact 45
member I1 is electrically connected to the chan
nel member by the flexible conductor 2I, which
is attached to these members by means of the
screws 22, 23 and 24.
'
The lower terminal member 46, as illustrated 50
in Figs. 1 and 2, is arranged with its lower por
tion extending forwardly, downwardly and then
upwardly from the outer end of the lower in
sulator I2, in the form of a hook-shaped yoke, to
provide a pair of bearing hooks 49. The upper 55
portion of the lower terminal member terminates
at its outer or forward end in the form of a yoke,
the arms of which are designated by the nu
meral 54.
Having described the mounting for the fuse
2
2,109,090
cartridge, we now describe the expulsion fuse
cartridge itself, with particular reference to Figs.
1, 3, 4, and 5.
The fuse tube or tubular insulator 25, of any
suitable insulating material adapted for expul
'sion fuses, such as ñber, is provided near its low
er end with the lowerl metal cartridge sleeve 50.
which is rigidly attached to the lower end of
l . the tubular insulator 25 by means of the screws
52. The metal sleeve 50, near its lower end, is
provided with the oppositely and laterally ex
tending integral pins 5|, of suitable size for rest
ing in and rotating about the hooks 49 of the
lower terminal member 46. A slotted portion 53
of the lower sleeve 50 extends outwardly there
from, and is threaded for cooperation with the
screw plug 41, for the purpose of clamping se
curely the lower end of the fuse link 42.
At its upper end, the fuse tube 25 has rigidly
20 secured thereto, by means of the pin 24, the up
per fuse cartridge sleeve 3|. An eye 33, for con'
venience in manually manipulating the switch,
is formed integrally with the sleeve 3|, and ex
tends outwardly therefrom from the lower por
tion thereof. Immediately above the eye 33, a
extending integral portions 4| of the fuse termi
nal 35.
In operating the device, the fuse link 42 is ñrst
dropped from the top through the fuse termi
nal 35 and the tubular insulator 25, and secured 5
to the former by the plug 38. 'I'he fuse link is
then passed through the closure 48, and the lat
ter pressed against the bottom of the fuse tube
25, and then crimped or squeezed on the lower
portion of the fuse link to retain the closure 48
in place. The closure 48 is conveniently made
of lead or any similar easily deformed metal. The
lower end of the fuse link 42 is then secured to
the lower fuse link terminal 53, as before des
scribed.
The fuse cartridge is then rotated on the piv
ots 5| from the position indicated by the broken
lines in Fig. 1 to the closed position shown by the
solid lines of the same figure.
It will now be ob
served that the upper end of the cartridge is 20
vented; the lower end is closed; and that the fuse
link is under tension due to the downward force
of the spring I8, which is transmitted about the
pivot 28 through the upper contact 26 of the fuse
cartridge to the outwardly extending` portions 4| 25
vent opening or recess 32 is formed, and arranged
of the fuse terminal 35. The cartridge is thus
to register with the opening 55 through the wall latched in the closed circuit position through the
of the tubular insulator 25. To prevent entrance l engagement of the detent means 4| with the up
of insects, the outer face of the vent 32 is pref
per contact member 26.
30 erably perforated, as indicated‘by the numeral
If, under these conditions, an 'excessive current 30
4I) in Fig. 5.
y
vfuses the fuse link 42, the internal pressure with
An integral portion of the sleeve 50 extends in the cartridge will ñrst be relieved through the
inwardly, in a direction opposite from that of the vent 32. The reaction from such exhaust is ob
vent, and has attached thereto, by means of the viously in a direction to rotate the fuse cartridge
35 pivot 28, the upper contact 26 of the fuse car
tridge. The contact 26 extends upwardly and
inwardly from the pivot 28, being rounded at its
upper end to provide, under conditions to be
later explained, a contact with the upper termi
Intermediate of the
40 nal member contact I1.
ends of its upwardly and inwardly extending por
tion, the upper contact 26 of the fuse cartridge
is provided with an integral portion arranged to
extend outwardly toward the upper end of the
fuse cartridge, this portion terminating in the
form of an open yoke, as shown in detail in Fig. 3.
The tubular metal upper fuse terminal 35 of
the fuse cartridge is arranged for reciprocatory
movement within the enlarged upper portion 39
50 of the fuse tube 25, and its`reciprocatory motion
is limited by the engagement of the upper and
lower end walls of the longitudinal recess 31 with
the retaining pin 34. 'I‘he upper end of the fuse
terminal 35 is arranged` with internal threads for
cooperation with the threads of the screw plug
_ 38, for attaching the upper'end of the fuse link
to the fuse terminal 35. A ñexible conductor 21,
attached at one end to the fuse terminal 35 by
means of the screw 29, and at the other end to the
60 upper contact 26 of the fuse cartridge by means
of the screw 30, provides a. path for shunting cur
rent around the pivot 28. An opening 36
through the wall of the fuse terminal 35 is ar
ranged to register with the openings 55 and 32
65 only when the fuse terminal 35 is in its lowermost
position, and to close the opening 55 upon up
ward movement of the fuse terminal 35 axially
with respect to the cartridge 25. The member
35 thus is a slide valve for opening and closing
'the opening 55, the latter extending laterally
through the wall of the cartridge 25 at the upper
end thereof. Also, when the latter condition ob
tains, the outer ends of the yoke portion of the
upper fuse cartridge contact 26 are arranged to
engage the bottom surfaces of a pair of laterally
in a. counterclockwise direction; that is, in a 35
direction to maintain the cartridge in the closed
position. In response to the rupture of the fuse
link, the closure 48 is removed from the lower
end of the cartridge as the fuse terminal 35 moves
upwardly to cut off the exhaust from the vent 32. 40
As the valve means comprising the members 35
and 32 shut oiï the vent at the upper end of the
cartridge, the upward movement of the fuse ter
minal 35 adds volume to the inside of the car
tridge to reduce impact. Also, the upward move
ment of the fuse terminal 35 permits the coun
terclockwise rotation of the upper fuse cartridge
contact 26 about the pivot 28 with respect to the
axis of the fuse cartridge under the influence of
the spring I8, thus releasing and forcing out 50
wardly from the upper terminal member the up
per end of the fuse cartridge. The cartridge
then assumes, under the influence of gravity, the i
full open switch position illustrated by thev broken
lines of Fig. 1.
rI‘he opening of the bottom of the cartridge,
when it is under high internal pressure, through
the removal of the closure 48, will tend to force
the cartridge upwardly. The resilient spring I8
absorbs the initial shock from such reaction, the 60
initial upward impact being transmitted from
the cartridge 25 to the spring I8 through the
members 3|, 28, 26 and |1. 'I'he upward mo
tion deforms the spring |8 an amount a little
less than the spacing between the member I1 65
and the member I6. 'I'he upward motion is lim
ited by the contact of the upper edge of the lower
fuse cartridge sleeve 50 with the underside of the
overhanging portions 54 of the lower terminal
member 46. The stressis thus divided between 70
the two insulators || and I2, instead of being
entirely imposed on one of them.
It may be noted that the drganization is such
that the port 32 is closed, and the closurel 48 is
ruptured, before the fuse cartridge 25 is un 75
2,109,090
latched.
Such an arrangement assures that the
arc within the cartridge 25 will be completely
extinguished before the member 26 moves away
from the member I1. In the event that the car
tridge 25 was not arranged to be held in position
by the recoil of the exhaust gases from the port
32 and the lower end of the cartridge until com
plete extinguishment of the circuit-interrupting
arc has occurred, then serious burning of the
members 26 and I1 would occur. In ourdevice,
under heavy currents, the arc may possibly be
extinguished before the port 32 completely closes.
Under relatively smaller currents, the internal
gas pressure will necessarily be less, and arc ex
tinguishment relatively more diñicult. -'I'he clos
ing of the port 32 under this condition before un
latching the cartrid-ge 25 leaves the latter vented
at only the lower end, resulting in higher inter
nal pressures at these current values and assur
said cartridge electrically connecting said termi
nal members, means controlled by tension in said
fuse link for maintaining said switch in the closed
position when said fuse link is unfused, and for
unlatching said cartridge and opening said
switch following the rupture of said fuse link,
said cartridge being vented at its upper end and
closed at its lower end when said fuse link is 10
intact, and- means responsive to the rupture of
said fuse link for opening the lower end of said
cartridge, said upper vent and the lower end of
said cartridge being related to each other and to
the other elements of said switch so that the 15
combined recoil due to the discharge of gas from
said cartridge maintains the latter in the closed
position.
4. In a fuse switch having an open and a closed
position, spaced insulated upper and lower ter 20
equivalent to that of cartridges open at both
minal members, a fuse cartridge pivoted on the
lower terminal member, a fuse link within said
the shock which might attend the sudden closing
of the port 32 by the valve 35 is cushioned by the
axial movement of the latter outwardly from the
tube, since this movement increases the internal
volume under pressure as the port 32 is closed.
Among other things, it may be noted that our
device cannot be placed in the service position
unless the opening 55 through the wall of the fuse
cartridge is open; also that the cartridge cannot
be unlatched from the upper terminal member
35 in response to the blowing of the fuse unless the
vent is closed, or after such time as the internal
pressure has been greatly reduced.
While we have herein specifically described one
embodiment of our invention for the purpose of
40 facilitating an understanding of its construction
and operation, it will be understood that changes
in this specific construction may be made without
departing from the principles of the invention.
_ We claim, as our invention:
1. A fuse switch comprising insulating means
having mounted thereon spaced insulated upper
and lower terminal members, a fuse cartridge
pivoted at its lower end 0n the lower terminal
member, a fuse link within said cartridge elec
50
ed on the lower terminal member and latched to
the upper terminal member, a fuse link within
ing arc extinguishment over a range of currents '
ends and open at only one end, this wide range
of effective arc extinguishment being attained
in a single device. It may also be observed that
30
3
trically connecting the terminal members, latch
means dependent upon tension in said fuse link
for maintaining the electrical connection, an
opening at the upper end of said cartridge and
a valve longitudinally movable along the axis
55 thereof for closing said opening, and _detent
cartridge electrically connecting said terminal
members, latch means combined with the upper
terminal member and controlled by tension in 25
said fuse link for maintaining said cartridge in
the closed position, said latch means including a
resilient member permitting an upward move
ment of said cartridge against the bias of said
resilient member in response to expulsion ac 30
tion within said cartridge, and means combined
with the lower terminal member for limiting the
upward travel of said fuse cartridge.
5. In a fuse switch having an open and a closed
position, spaced insulated upper and lower termi
lower terminal member, a fuse link within said
cartridge electrically connecting said terminal
members, latch means combined with the upper
terminal member and controlled by tension in 40
said fuse link for maintaining said cartridge in
the closed position, said latch means including a
resilient member permitting an upward move
ment of said cartridge against the bias of said re
silient member in response to expulsion action 45
within said cartridge, and means including a
member rigidly secured to said lower terminal
member and positioned in the path of upward
movement of a portion of said fuse cartridge
for limiting the upward travel thereof.
50
6. A fuse switch comprising insulating means
having mounted thereon spaced insulated upper
and lower terminal members, a fuse cartridge
pivoted at its lower end on the lower terminal
member, a fuse link within said cartridge electri 55
means carried by said valve, said detent means
cally connecting the terminal members, latch
beingarranged to prevent movement of said latch
means dependent upon tension in said fuse link
for maintaining the electrical connection, an
opening at the upper end of said cartridge and a
means in response to the rupture of said fuse
link when said opening is open.
2. In a fuse switch, spaced insulated upper
60
and lower terminal'members, a fuse cartridge
pivoted on the lower terminal -member and
latched to the upper terminal member, a fuse link
within said cartridge electrically connecting said
6 lil terminal members, means controlled by tension
in said fuse link for maintaining said switch in
the closed position when said fuse link is unfused,
and for unlatching said cartridge and opening
said switch following the rupture of said fuse link,
said cartridge being vented at its upper end, said
vent being arranged so that the recoil due to dis
charge of gas therethrough maintains the car
tridge in the closed position.
3. In a fuse switch, spaced insulated upper and
75 lower terminal members, a fuse` cartridge pivot
35
nal members, a fuse cartridge pivoted on the
valve longitudinally movable along the axis 60
thereof for closing said opening, and detent
means carried by said valve, said detent means
being positioned externally of said cartridge and
arranged to actuate said latch means in response
65
to rupture of said fuse link.
'7. A fuse switch comprising insulating means
having mounted thereon spaced insulated upper
and lower terminal members, a fuse cartridge
pivoted at its lower end on the lower terminal
member,.a fuse link within said cartridge electri 70
cally connecting the terminal members, latch
means dependent upon tension in said fuse link
for maintaining the electrical connection, an
opening at the upper end of said cartridge and
a valve longitudinally movable along the axis 75
4
2,109,090
thereof for closing said opening, said valve in
cluding detent means positioned externally of
said cartridge and arranged to actuate said latch
means in response to a movement of said- valve
in a direction to close said opening.
8. A fuse switch comprising insulating means
having mounted thereonspaced insulated upper
and lower terminal members, a fuse cartridge piv
oted at its lower end on the lower terminal mem
10 ber, a fuse link Within said cartridge electrically
connecting the terminal members, latch means
dependent upon tension in said fuse link for
maintaining the electrical connection, an open
ing at the upper end of said cartridge and a valve
15
longitudinally movable along the axis thereof for
closing said opening, said valve including detent
means positioned externally of said cartridge and
arranged to restrain movement of said latch
means when said opening is open and to release
said latch means in response to movement of said
valve in a direction to close said opening.
9. An expulsion fuse comprising a hollow tube
of insulating material, conducting contacts at the
respective ends of said tube, one of said contacts
being formed with an opening communicating
with the interior of said tube, a valve movable be
tween the open and the closed position associated
with said opening, and a fuse link within said
tube electrically connecting said contacts, said
30 fuse link being fastened to said valve and ar
ranged to hold said valve in the open position
when said fuse link is unfused.
10. An expulsion fuse comprising a hollow tube
of insulating material, conducting contacts at the
respective ends of said tube, one of said contacts
being formed with an opening communicating
with the interior of said tube, a valve movable
between the open and the closed position asso
ciated with said opening, and a fuse link within
40 said tube electrically connecting said contacts,
said fuse link being secured to said valve and ar
ranged to normally hold said valve in the open
- position.
11. An expulsion fuse comprising a hollow tube
45 of insulating material, conducting contacts at the
respective ends of said tube, one of said contacts
being formed with an opening communicating
with the interior of said tube, a valve movable
between the open and the closed position asso-V
50 ciated with said opening, a. fuse link within said
13. The combination in an expulsion fuse nor
mally having an opening at one end thereof in
communication with the interior of said fuse and
means closing the other end of said fuse, of means
responsive to the blowing of said fuse for closing
the opening at said one end and removing the
means closing said other end.
14. An expulsion fuse comprising a hollow tube
of insulating material, conducting contacts at the
respective ends of said tube, one of said contacts 10
being formed with an opening in communication
with the interior of said tube, a fuse link within
said tube electrically connecting said contacts, a
movable valve arranged to close said opening, one
end of said fuse link being fastened to said valve
whereby the movement thereof is restrained when
said fuse link is unfused and released upon the
fusing of said fuse link, and means for generating
a gas under pressure within said tube in response
to the fusing of said fuse link, the arrangement 20
being such that said valve is actuated to close
said opening in response to the gas pressure within
the tube.
15. An expulsion fuse comprising a hollow tube
of insulating material, conducting contacts at the
respective ends of said tube, one of said contacts
being formed with an opening in communication
with the interior of said tube, a fuse link within
said tube electrically connecting saidvcontacts, a
movable valve arranged to close said opening, one 30
end of said fuse link being fastened to said valve
whereby the movement thereof is restrained when
said fuse link is unfused and released upon the
fusing of said fuse link, means for initiating an
arc within said tube in response to the fusing of 35
'said fuse link, and means dependent upon the
duration of said arc for actuating said valve to
close said opening.
16. An expulsion fuse comprising a hollow tube
of insulating material, conducting contacts at the 40
respective ends of said tube, one of said contacts
being formed with an opening in communication
with the interior of said tube, a fuse link within
said tube electrically connecting said contacts, a
movable valve arranged to close said opening, one 45
end of said fuse link being attached to said valve
whereby the movement thereof is restrained when
said fuse link is unfused and released upon the
fusing of said fuse link, means responsive to an
arc within said tube for generating a gas under 50
tube electrically connecting said contacts, and
pressure therein upon the fusing of said fuse link,
fuse terminals externally of said tube for engag
ing the respective ends of said fuse link, said fuse
link being fastened to said valve and arranged
to hold said valve in the open position when said
fuse link is unfused.
12. An expulsion fuse comprising a hollow tube
of insulating material, conducting contacts at the
respective ends of said tube, one of said contacts
60 being formed with an opening communicating
and means responsive to the gas pressure for
with the interior of said tube, a valve movable
between the open and the closed position asso
ciated with said opening, a fuse link within said
tube electrically connecting said contacts, and
fuse terminals externally of said tube for engaging
the respective ends of said fuse link, said fuse
link being fastened to said valve and arranged to
hold said valve in the open position when said
fuse link is unfused, and to release said valve in
70 response to the blowing of said fuse, the arrange
ment being such that said valve moves in re
sponse to pressure within said tube to the closed
position.
actuating said valve to close said opening and
change the direction of discharge of said gas
from said tube whereby said arc is extinguished.
17. -A fuse- switch comprising insulating means
having mounted thereon spaced upper and lower
terminal members, a fuse cartridge pivoted at its
lower end on the lower terminal member, an open
ing at the upper end of said cartridge and a 60
valve for closing said opening, a fuse link within
said cartridge electrically connecting the terminal
members, one end of said fuse link being fastened
to said valve- and arranged to hold said valve
in the open position, latch means dependent upon 65
tension in said fuse link for maintaining the elec
trical connection, and detent means carried by
said valve externally of said cartridge and in en
gagement with said latch means, the arrangement
being such that said valve is movable to the closed 70
position independent of said latch means.
RALPH R. PI'ITMAN.
CARROLL H. WALSH.
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