Europaisches Patentamt
(19)
European Patent Office
Office europeen
brevets
peen des brevets
EP0
696
811
B1
E U R O P E A N PATENT S P E C I F I C A T I O N
(12)
(45) Date of publication and mention
of the grant of the patent:
17.12.1997 Bulletin 1997/51
(51) intci.e: H01H 37/76, H01H 9 / 1 0
(21) Application number: 95500119.3
(22) Date of filing: 10.08.1995
(54) Improved fuse fitted in the thermostat of a home electrical appliance
Verbesserte Sicherung eingebaut im Thermostaten eines Haushaltsgerates
Fusible ameliore monte dans le thermostat d'un appareil electromenager
(84) Designated Contracting States:
DE FR IT PT
(72) Inventor: Ormaechea Laborda, Ignacio
E-20600 Eibar (Guipuzcoa) (ES)
(30) Priority: 12.08.1994 ES 9402202
(43) Date of publication of application:
14.02.1996 Bulletin 1996/07
(74) Representative: Carpintero Lopez, Francisco
HERRERO & ASOCIADOS, S.L.
Alcala, 21
28014 Madrid (ES)
(73) Proprietor: OFICINA DE INVESTIGACION
AGRUPADA, S.A.
20600 Eibar (Guipuzcoa) (ES)
(56) References cited:
DE-A- 2 339 674
US-A-3 611 235
GB-A- 1 540 088
US-A- 4 720 759
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Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give
notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in
a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art.
99(1) European Patent Convention).
Printed byJouve, 75001 PARIS(FR)
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EP 0 696 811 B1
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of a material that melts at a suitable temperature, whereas the other end stays free and constitutes a fast connection.
OBJECT OF THE INVENTION
The insulating box is made of a self-extinguishing
The present invention relates to a safety fuse for s material, is mounted directly on the thermostat terminal,
and internally comprises two parallel channels that are
home electrical appliances of all kinds, fitted at one of
the available thermostat terminals in order that when the
respectively designed to house the two ends of the conthermostat stops working properly, either because the
ducting strip. The upper channel houses the thermostat
terminal and one of the ends of said strip, and thus for
connections are welded together or the bimetallic strip
is deformed or otherwise whatsoever, and the temper- 10 the two to be connected, the strip end is bent until it contacts the terminal and is then soldered with a material
ature of the appliance rises alarmingly, the conductor
having a suitable melting point. On the other hand, the
joined to the thermostat through the fuse will be broken
lower channel houses the other end of the strip, that
off by fusion of the latter.
passes through the said channel to leave its end free for
is connection to be made as appropriate to the terminal
BACKGROUND OF THE INVENTION
used.
The strip end soldered to the thermostat terminal is
In home electrical and appliances of any other kind
therefore live, housed inside the insulating material box,
whatsoever which require a safety thermal device, such
and so when the point of soldering is worn down by acdevice usually comprises afuse mounted independently
of the thermostat, i.e. connected to a terminal other than 20 tion of the heat the strips comes off the terminal and its
end folds up to contact with the roof of the insulating
the thermostat terminals.
One such device, which is the least used and known
plastic box, moving back to its initial position and hence
breaking off the passage of current through it, ensuring
as the minimet, is mounted inside an insulating ceramic
that the appliance is switched off forthwith.
box having a fixing plate. Devices of this kind work well
but their high cost renders them rather unsuitable to be 25
DESCRIPTION OF THE DRAWINGS
used in small appliances in which the end prices and
hence profit margins are not very high.
In ordertoprovideafuller description and contribute
The device that is currently used most is mounted
inside a cylindrically-shaped metal cartridge. This deto the complete understanding of the characteristics of
vice costs less than the above-mentioned device but is 30 this invention, a set of drawings is attached to the specification which, while purely illustrative and not fully comshorter-lived and is moreover inconvenient in that if not
prehensive, shows the following:
suitably insulated dielectric strength problems ensue.
Another disadvantage of the systems described
Figure 1.- Shows three views of a thermostat withabove and currently used is how rapidly appliances usout the fuse subject of the invention.
Figure 2.- Shows three views of a thermostat with
ing fuses of this kind age, and an improvement of this 35
the
fuse
would
therefore
be
welcome.
subject of the invention fitted.
aspect
The application of the system subject of the invenFigure 3.- Shows two cross-sections of the fuse
tion brings down the cost of the appliance and extends
subject of the invention, where it can be seen with the
its life for it transmits the temperature at points that are
contact made.
40
far less critical than pure connection points.
Figure 4.- Shows two cross-sections of the fuse
From US-A-4,720,759 there is known a fuse fitted
subject of the invention, where it can be seen with the
in a thermostat wherein one of the two connections, becontact broken off.
tween which the thermostat is fitted, is provided with a
PREFERRED EMBODIMENT OF THE INVENTION
conducting strip soldered at one end to a terminal, an
insulating box being provided, in order that when the 45
connection between the strip and said terminal is broken
With reference to the figures, the fuse subject of the
due to flowing and melting of the solder, the one end will
invention is arranged at one of the thermostat terminals
be released from the joint fixing it to the terminal and
and comprises a conducting strip and an insulating
rise upwardly, driven by a certain spring-like effect, to
member (3), forming a sort of hollow box, with a midlie at a sufficient distance from the terminal and avoid so wall (4) that defines two parallel channels inside the box
the passage of current between the two.
(3), an upper (5) and a lower (6) channel, for the said
strip to be housed.
This box (3) has a slot (9) designed to be fitted diDESCRIPTION OF THE INVENTION
rectly onto the terminal (2), the said terminal being arThe present invention lies in the use of a safety fuse 55 ranged inside the upper channel (5) and slightly above
mounted at one of the thermostat connections, which
the mid-wall (4), passing through the box (3) and ending
fuse comprises an insulating box and a conducting strip
(2) in an upwardly folded extension entwined about the
that is soldered at one end to the connection by means
box (3) locking it in such position.
Description
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EP 0 696 811 B1
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The conducting strip (7) is arranged inside the box
Patentanspriiche
(3), folded, as shown in figure 3, to achieve a better
1. Verbesserte Sicherung, eingebaut im Thermostat
spring effect between its ends, and thus it defines a short
eines Haushaltsgerats, bei welchem in eine der beiend (7') and a long end (7") with longitudinal grooves to
s
den Klemmen, zwischen denen sich der Thermomake up a fast coupling.
The long end (7") of the strip (7) is housed in the
stat befindet, ein in der Mitte gebogenes Leitband
lower channel (6) and passes through the same to leave
(7) eingesetzt wird, dessen eines Ende (7') an eine
Klemme (2) angelotet wird, wahrend das andere
its end free, thereby to allow an easy connection thereto.
Ende (7") einen Schnellverbindungspunkt darstellt
On the other hand, the short end (7') of the strip (7)
und daneben ein Isolierkasten (3) vorgesehen ist,
is arranged inside the upper channel (5) and locked to 10
der innen durch eine Trennwand (4) in zwei paralthe terminal by means of a point of soldering (8) having
lel Kanale (5) und (6) geteilt wird, womit das ana suitable melting point, thereby allowing the passage
dere Ende (7") des Bandes (7) im unteren Kanal (6)
of current when the thermostat makes connection between terminal (1) and terminal (2).
liegt und diesen vollstandig durchquert, wahrend
sich das erste Ende (7') im oberen Kanal (5) befinWhen the temperature that terminal (2) acquires is 15
det und mittels der Lotstelle (8) mit der Klemme (2)
too high, due to the intensity that flows through the
in der Weise verbunden wird, dass das erste Ende
and
the
thermostat
has
broken
off
the
not
same,
pasof
the
solder
will
melt
the
effect
of
current
(8)
by
(7') bei Aufhebung des Kontakts zwischen dem
sage
the said temperature and the strip (7) will be free from
Band (7) und der genannten Klemme (2) infolge eithe joint holding it connected to the terminal (2) and will, 20
nes ubermassigen Anstiegs der Temperatur auf
due to the above-mentioned spring effect, have its short
Grund einer sehr hohen Stromstarke aus der Verend (7') rise to touch the roof of the box (3), thereby bebindung, welche es an der Klemme (2) halt, freigegeben und durch eine gewisse Federwirkung nach
ing sufficiently separated from the terminal (2) to ensure
oben geklappt wird, bis es mit der oberen Wand des
that they are not connected again accidentally.
Kastens (3) in Beruhrung kommt und einen ausreiWe feel that the description need not be extended 25
chenden Abstand von der Klemme (2) gewinnt, urn
any longer for any expert in the art to have grasped the
den Stromdurchgang zwischen beiden zu verhinfull scope of the invention and the advantages it offers.
dern.
The materials, shape, size and layout of the elements may be altered provided that this entails no modification of the essential features of the invention, as de- 30
Revendications
fined by the claim.
Claims
1.
A fuse fitted in the thermostat of a home electrical
appliance, wherein one of the two connections, between which the thermostat is fitted, is provided with
a conducting strip (7) folded at the centre and soldered at one end (7') to a terminal (2), whereas the
other end (7") constitutes a fast connection point,
an insulating box (3) being provided, which box is
internally divided by a wall (4) into two parallel channels (5) and (6) such that the other end (7") of the
strip (7) is housed in the lower channel (6) fully
passing through the same, whereas the one end (7')
is arranged inside the upper channel (5) and locked
to the terminal (2) by soldering (8) in orderthat when
the connection between the strip (7) and the said
terminal (2) is broken due to the excesive elevation
of the temperature provoked by the strong intensity
flowing through the same and melting the solder (8),
the one end (7') will be released from the joint fixing
it to the terminal (2) and rise upwardly, driven by a
certain spring-like effect, until it contacts the roof of
the box (3) to lie at a sufficient distance from the
terminal (2) and avoid the passage of current between the two.
1.
35
40
45
so
55
3
Fusible monte dans le thermostat d'un appareil
electromenager, ou dans I'une des deux bornes, entre lesquelles est intercale le thermostat, est installe
un ruban conducteur (7), plie a sa partie centrale,
en soudant a I'une de ses extremites (7') une borne
(2), tandis que I'autre extremite (7") constitue un
point de connexion rapide, en ayant prevu une boTte
isolante (3), divisee a I'interieur, par une cloison (4),
en deux canaux paralleles (5) et (6), de sorte que
I'autre extremite (7") du ruban (7) soit loge dans le
canal inferieur (6) en traversant completement ce
dernier, tandis que la premiere extremite (7') est situee a I'interieur du canal superieur (5) en se solidarisant a la borne (2), a I'aide de la soudure (8),
de sorte que lors de la dematerialisation du contact
entre le ruban (7) et cette borne (2), a cause de I'elevation excessive de la temperature provoquee par
la forte circulation d'intensite qui fait fondre la soudure (8), la premiere extremite (7) soit liberee de
I'union qui la fixe a la borne (2), en se pliant vers le
haut, pousse par un certain effet ressort, jusqu'a
etablir un contact avec la cloison superieure de la
boTte (3), en restant a une distance suffisante par
rapport a la borne (2) pour eviter le passage du courant entre les deux.
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