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US 5,023,744 AGranted
Temperature switching device
OwnerPeter Hofsassinventor
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OwnerPeter Hofsassinventor
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A temperature switching device for an electrotechnical part to be protected against an excess temperature due to a fault, with a first bimetallic switch and an ohmic resistor connected in parallel thereto, so that, after opening the bimetallic switch as a result of an excess temperature, the flow of current takes place across the ohmic resistor, which produces heat and as a result the bimetallic switch is kept open even in the case of the cooling of the excess temperature initially triggering the switching process due to a malfunction of the electrotechnical part to be protected, as a result of the evolution of heat of the ohmic resistor. At least the ohmic resistor is connected in series with a further automatically resettable thermal switch having an opening temperature above that of the first thermal switch, but well below temperatures causing irreversible damage to bimetallic elements and the two thermal switches being in close thermal contact.
Temperature switching device for an electrotechnical part to be protected against an excess temperature due to a malfunctioning of the electrotechnical part, the temperature sensitive device including a first thermal switch means, an ohmic resistor means connected in parallel to said first thermal switch means, said first thermal switch means being adapted to be opened as a result of an excess temperature so that a flow of current takes place across the ohmic resistor means, and at least one automatically resettable second thermal switch means having an opening temperature above an opening temperature of the first thermal switch means but well below temperatures causing irreversible damage to bimetallic elements of the first and second thermal switch means such that heat produced as a result of the flow of current across the ohmic resistor means does not maintain the first thermal switch means in an open position upon a cooling of the excess temperature initially triggering the switching process of the first thermal switch means, and wherein the two thermal switch means are in close thermal contact.
A temperature switching device comprising a first thermal switch means, and ohmic resistor means connected in parallel to said first thermal switch means, and a second thermal switch means connected in series with the at least one ohmic resistor means, and wherein the second thermal switch means has a higher opening temperature than an opening temperature of the first thermal switch means in order to protect the first thermal switch means.
A thermal switch in a temperature switching device including a self-holding thermal switch means and a resistor means arranged in parallel to the self-holding thermal switch means, said thermal switch having an opening temperature higher than an opening temperature of said self-holding thermal switch means so as to protect the self-holding thermal switch means against damage due to an excessive temperature brought about by the parallel connected resistor means.
Dependencies are inferred from the claim text.