AUTOMATIC TEMPERATURE CONTROL DEVICE FOR ELECTRIC BLANKET
First Claim
1. An automatic temperature control device for use with an electric blanket, comprising a heating wire, a heat-sensitive layer formed over the entire length of said heating wire and consisting of a flexible solid organic material having a negative resistance temperature coefficient and adapted to become conductive to such an extent as to pass a current sufficient to cause a controlling action when heated to a certain temperature or higher, a signal wire provided opposite to said heating wire with said heat-sensitive layer intervening therebetween, a relay for operating a make-and-break contact connected in series with said heating wire, a transistor for actuating said relay, and an input and output resistors and a rectifier for said transistor, said transistor having the collector thereof connected to one end of the output resistor through the relay and the emitter thereof connected with the other end of said output resistor and the base thereof connected to the connection between said relay and said output resistor through a series circuit consisting Of said signal wire and said input resistor, and said output resistor being connected to a power source through said rectifier.
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Accused Products
Abstract
Improvements of the automatic temperature control device in an electric blanket for ordinary household use, removing troubles and high cost caused by employing a delicate relay, premature deterioration of a heat-sensitive layer, inconvenience in reheating after breaking of a switch due to abnormal overheating of a heating wire, etc. by means of an improved automatic control device.
14 Citations
3 Claims
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1. An automatic temperature control device for use with an electric blanket, comprising a heating wire, a heat-sensitive layer formed over the entire length of said heating wire and consisting of a flexible solid organic material having a negative resistance temperature coefficient and adapted to become conductive to such an extent as to pass a current sufficient to cause a controlling action when heated to a certain temperature or higher, a signal wire provided opposite to said heating wire with said heat-sensitive layer intervening therebetween, a relay for operating a make-and-break contact connected in series with said heating wire, a transistor for actuating said relay, and an input and output resistors and a rectifier for said transistor, said transistor having the collector thereof connected to one end of the output resistor through the relay and the emitter thereof connected with the other end of said output resistor and the base thereof connected to the connection between said relay and said output resistor through a series circuit consisting Of said signal wire and said input resistor, and said output resistor being connected to a power source through said rectifier.
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2. An automatic temperature control device for use with an electric blanket, comprising a heating wire, a heat-sensitive layer formed over the entire length of said heating wire and consisting of a flexible solid organic material having a negative resistance temperature coefficient and adapted to become conductive to such an extent as to pass a current sufficient to cause a controlling action when heated to a certain temperature or higher, a signal wire provided opposite to said heating wire with said heat-sensitive layer intervening therebetween, a relay for operating a make-and-break contact connected in series with said heating wire, a transistor for actuating said relay, an input and output resistors and a rectifier for said transistor, a dividing resistor and a constant-voltage element, said transistor having the collector thereof connected to one end of the output resistor through the relay and emitter thereof connected to the other end of said output resistor and the base thereof connected to the connection between said relay and said output resistor through a series circuit consisting of said signal wire and said input resistor, and said output resistor having said constant-voltage element connected therewith in parallel and being connected to a power source through said dividing resistor and said rectifier.
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3. An automatic temperature control device for use with an electric blanket, comprising a heating wire, a heat-sensitive layer formed over the entire length of said heating wire and consisting of a flexible solid organic material having a negative resistance temperature coefficient and adapted to become conductive to such an extent as to pass a current sufficient to cause a controlling action when heated to a certain temperature or higher, a signal wire provided opposite to said heating wire with said heat-sensitive layer intervening therebetween, a relay for operating a make-and-break contact connected in series with said heating wire, a transistor for actuating said relay, and an input and output resistors and a first and second rectifiers for said transistor, said transistor having the collector thereof connected to one end of the output resistor through the relay and the emitter thereof connected to the other end of said output resistor and the base thereof connected to the connection between said relay and said output resistor through a series circuit consisting of said signal wire and said input resistor, said first rectifier being connected between said base and said emitter in a direction opposite to the flow direction of the emitter current and said output resistor being connected to a power source through said second rectifier.
Specification