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Patented Oct. 29,1946 \
2,410,244
UNITED STATES PATENT OFFICE
2,410,244
FUSE
William 0. Schultz, South Milwaukee, Wis., as
signor to Line Material Company, Milwaukee,
Wis., a corporation of Delaware
Application June 25, 1943, Serial No. 492,291
I
5 Claims.
This invention relates to power fuses and more
particularly to fuses of the bayonet type.
In certain cases where bayonet type fuses are
employed it is desirable to use standard fuse
links of the type which does not include a built
in biasing ‘spring; but at the same time it often
is- desirable or necessary to provide suitable spring
means operative to bias the link and thereby
quicken the separation of severed fuse-link parts
when blowouts occur.
The primary object of the present invention is
to devise a practical fuse construction which
is Well adapted to utilization of standard links
(Cl. 200-117)
2
readiness to function as an expeller in event of a
blowout.
-
A preferred embodiment of the invention is il
lustrated by the accompanying drawing, where
of:
~ .
Fig. l is a sectional view depicting the lower
end portion of a bayonet fuse housing together
with a fuse-cartridge and fuse-link-the ‘car
tridge and link being shown during an intermedi
ate stage of link installation;
~
Fig. 2 is substantially a repetition of the lower
portion of Fig. 1, except that it depicts the fuse
link fully installed and shows the ears of the
metal clip bent to effect an anchorage of the
of the above-indicated variety while providing
the desired spring bias.
15 fuse-link to the cartridge terminal and biasing
Another object is to achieve simplicity of design
spring;
.
and consequent manufacturing economy.
Fig. 3 is a view taken along the line 3--3 of Fig.
Still another object is to facilitate the installa
2; and
tion of replacement fuse-links so that servicing
Fig. 4 is a view taken along the line 4—4
of the fuses in the ?eld will not be inordinately 20 of Fig. 2
‘
time-consuming or entail the exercise of any con
Inasmuch as the present invention is not con
siderable skill.
cerned with the fuse housing construction, there
A further object is to provide a movable spring
has been shown only the lower portion of such a
biased fuse-link engaging member urged to fuse
housing. This comprises a tubular porcelain
link extracting position and normally engaged 25 housing member I, shown fragmentarily, in which
by a resilient friction contact which relieves the
fuse-link of excessive stresses while the fuse-car- ‘
is located a conductive sleeve 2 secured within the
housing by means of a cement or fusible metal
tridge containing the fuse-link is in circuit clos
?ller 3. Sleeve 2 is suitably apertured at 2a to
ing position, and also to so correlate the biasing
receive a line conductor and is provided with one
spring with the fuse structure as to protect it 80 or morebinding screws 4 by means of which the
from the destructive effects of an are upon rup
line conductor is clamped. The sleeve is bored
ture of the fuse link.
at 2?) concentrically with the housing to receive
' A prominent feature of the present invention
and make electrical contact with the lower termi
resides in a novel fuse-cartridge terminal con
nal of the fuse-cartridge, which latter is insertable
struction which incorporates within itself both a
85 into and withdrawable from said sleeve via the
biasing spring and contact members, so vco
upper end of the housing.
ordinated as to facilitate insertion and withdrawal
The fuse-cartridge comprises an elongate tube
of the cartridge into and from the fuse hous
5 of horn ?ber or, preferably, of “Bakelite” lined
ing without requiring any electrical connection
with horn ?ber, and is threaded externally at its
to be made by the serviceman after the cartridge 40 upper end to receive a ferrule '6 which, in turn is
is ‘in place, and so designed that the fuse-link
threaded to receive a removable conductive cap ‘I.
is properly and fully spring-biased before the
The upper ferrule and cap designs are to be re
cartridge is inserted in the housing, and so con
garded as purely conventional and subject to a.
tinues thereafter.
variety of modi?cations. The invention does not
Another feature consists in the provision of a 45 lie in that part of the structure.
simple metal terminal clip which can easily be
There is secured to tube 5, toward the lower
applied to the ?exible leader of a standard fuse
- end, a metal thimble 8. This encircles the tube
link and which is of such dimensions that it can
and provides support for the upper end of a
be passed through the fuse cartridge bore while
tubular member 9 which is slotted lengthwise to
attached to the fuse-link leader and thereafter 50 form several depending resilient contact ?ngers
bent, without di?iculty, so as to effect an anchor
9a spaced circumferentially about tube 5. These
ing engagement and good electrical contact be
contact ?ngers are yieldable radially of the tube
tween the fuse-link and the adjacent cartridge
and are designed to eifect spring-pressed en
terminal while contemporaneously retaining the
gagement with the bore 2b of sleeve 2.
biasing spring under compression and. thus in 55 The lower end of thimble 8 is of reduced di
2,410,244
4
ameter and threaded to engage the upper end of
a helical spring H) for which it affords an an
chorage. Said spring encircles the lower end of
tube 5 and is secured at its lower end to a ter
minal member II, which is supported by the
spring and is movable axially of tube 5 by stretch
ing and compressing the spring.
The spring I0 is disposed, in its entirety, ex
teriorly of the tube 5 and the terminal member
the frictional engagement of the contact ?ngers
9a with the terminal member H and conductive
sleeve 2 will be of suf?cient magnitude to effec
tively counteract the expansive force of the
spring I!) and thus relieve the fuse-link l2 of
the greater part of the stresses which would
otherwise be imposed thereon by the expansive
forces of the spring. It will of course be under
stood that frictional forces exerted by the con
ll. Consequently, any are established during 10 tact ?ngers 9a will not entirely overcome the ex
pansive forces of the spring l0 since the spring
circuit operations will not cause injury to the
must be free to withdraw the flexible leader 15
spring since the latter is positioned out of the
upon rupture of the fusible section 13 of the
path of hot destructive gases generated by the
fuse~link.
are and expelled from the tube.
When the fuse-link blows, spring I0 is effec
The fuse link 12 is of a standard type com 15
tive quickly to withdraw and expel from the
prising a fusible section l3 together with a but
cartridge all that portion of the fuse-link which
ton-head upper terminal l4 and a ?exible conis below the point where disjunction occurs.
ductive leader [5. Button head terminal I4 is
What is claimed is:
gripped between ferrule 6 and cap ‘I and serves
1. In combination, a fuse~cartridge, a fuse
as means for supporting the link at'its upper end 20
link within said cartridge and having a terminal
as well as for effecting electrical connection
anchored at one end of said cartridge, the other
thereto.
end of said cartridge being open, said fuse-link
A tubular metal clip 16 is compressed upon and
including as its second terminal an elongate con
thereby secured to leader H3 at a predetermined
ductive leader projecting out of said open end of
point. As shown in Fig. 1, clip 15 has two_o-pthe cartridge, a helical spring encircling said
posite downwardly extending pliable ?ngers Ilia
cartridge adjacent said open end, one end only
and Nib, which ?ngers are designed to be bent
of said spring being anchored to said cartridge
outwardly and upwardly, as shown in Fig. 2, to
at a point somewhat removed from the open end
hookingly engage terminal member I l-see Figs.
thereof, a tubular member encircling said spring
2 and 3.
and attached at one end to said cartridge, said
Since the fuse-link must be inserted in the
tubular member comprising a plurality of resili
cartridge from the upper end thereof, it is ob
ent contact ?ngers extending lengthwise of said
vious that metal clip l5 must initially be dicartridge, and means carried by said leader for
mensioned to pass through the bore of tube 5.
anchoring said leader to the unanchored end of
Hence, ?ngers lSa and [6b are made to extend
said spring for maintaining said spring under
parallel to leader l5, as shown in Fig. l, but
capable easily of being bent to form laterally
compression and said fuse-link under tension,
extending ears, as shown in Fig. 2, after the
said means being engaged by said resilient con
tact ?ngers whereby the expansive force of said
fuse-link is in place.
'
When the fuse-link is fully installed, spring
spring is in part nulli?ed.
I0 is under compression and the link correspond
2. In a fuse of the class described, a fuse car
ingly under tension; but when free, the spring
tridge having an open end, an expansible spring
encircling said open end and having one end
thereof secured to said cartridge at a point re
is extended lengthwise so that terminal member
ll occupies a lower position, as indicated in dot
and dash lines in Fig. 1. Said spring must be
compressed by forcing terminal member (I to
approximately the position in which it is shown
in full lines in Fig. 1, before the ?ngers lSa and
46b are bent outwardly and upwardly, per Fig. 2,
mote from said open end, a tubular terminal se
cured to the other end of said spring having a
bore concentric with and receiving the open end
of said tube, said tubular terminal in part being
encircled by said spring, a contact member se
to form the aforementioned ears which hooking~ 50 cured to said cartridge and encircling said spring
ly engage said terminal member. Whenever
and said terminal, said contact member includ
necessary, ?ngers 16a and [6b can be bent back
ing contact ?ngers frictionally engaging said ter
to approximately their original form, thus per
minal, and a fuse link engaging said terminal and
mitting the fuse~link to be removed from the
normally holding said spring under compression.
cartridge.
3. In combination, a fuse cartridge, a fuse link
Terminal member I I is contacted by the lower
of the standard type within said cartridge having
ends of contact ?ngers 9a, thereby establishing
a terminal anchored at the upper end of said
a conductive path via said contact ?ngers be
cartridge, the other end of said cartridge being
tween sleeve 2 and terminal member I l . Accord
open, said fuse link having as its other terminal
ingly, spring II] is not required to carry enough 60 a flexible conductive leader projecting out of the
current to cause injury thereto.
open end of the cartridge, a spring encircling
Terminal member II is, preferably, a brass
said cartridge at its lower end and having one
casting formed to present at its lower end two
end anchored thereto, a terminal member car
spaced parallel ?at sides which, in Fig. 3, are
ried by the other end of said spring at a point
identi?ed by reference numerals Ila and llb. 65 adjacent the open end of said cartridge, said ter
Said ?at sides are effective to provide ample con
minal member having a passageway co-termi
tact area with ears Ilia and l?b, while at the
nous with said open end of the cartridge and gen
same time serving to prevent rotation of clip !6
erally coaxial therewith, a metal clip attached to
relatively to said terminal member after the link
said flexible leader and having a plurality of pli
is installed.
70 able ?ngers which initially extend generally par
The resilient contact ?ngers 9a frlctio-nally en~
allel to said leader so as to enable said clip to
gage the terminal member H and are bowed
pass through the bores of said cartridge and ter
radially outwardly of the tube 5, as clearly illus
minal member, said ?ngers being bent after
trated in the drawing, to frictionally engage the
passing through the bores of said cartridge and
conductive sleeve 2. It is contemplated that 76 terminal member to form ears projecting radi
2,410,244
5
ally from said leader and engaging said terminal
member whereby said spring is maintained un
der compression and said fuse link is tensioned,
and a, resilient contact carried by said cartridge
frictionally engaging said terminal member to
provide a counteracting force which in part nul
li?es the expansive force of said spring.
4. In combination, a fuse cartridge, a fuse link
having a ?exible leader within said cartridge and
5. In combination, a fuse cartridge, a fuse
link having a ?exible leader Within said cartridge
and having a terminal anchored at the upper end
of said cartridge, the other end of said cartridge
being open, a spring encircling said cartridge at
its lower end and having one end anchored
thereto, a tubular terminal member carried by
the other end of said spring and having a bore
concentric with and receiving the open end of
having a terminal anchored on one end of said 10
said tube, said ?exible leader having at its lower
cartridge, the other end of said cartridge being
end a plurality of bendable arms, said arms be
open, a biasing spring encircling said cartridge
ing bent after passing through the bores of said
near the open end thereof, and having one end
cartridge and terminal member to form ears pro
anchored to said cartridge, a movable terminal
jecting radially from said leader and being effec
member carried by the other end of said spring, 15 tive to hold said spring under compression and
said fuse link including as its second terminal a
to tension said fuse link, and a resilient contact
pair of bendable arms, said arms, when bent, be
ing operative to engage said movable terminal
member and to hold said spring under compres
sion and said fuse link under tension, and a re
silient contact carried by said cartridge friction
ally engaging said movable terminal member
and in part nullifying the forces imposed on said
fuse link by said spring.
‘
carried by said cartridge frictionally engaging
said terminal members to provide a counteract
ing force which in part nulli?es the expansive
20 force of said spring.
WILLIAM O. SCHULTZ.
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