초록 ▼

A heating body includes a layered structure consisting of a resistive body and a control body, with a meltable insulating sheet therebetween. The control body contains wires which are brought into electrical contact with the resistive body if the temperature of the resistive body exceeds the melting

A heating body includes a layered structure consisting of a resistive body and a control body, with a meltable insulating sheet therebetween. The control body contains wires which are brought into electrical contact with the resistive body if the temperature of the resistive body exceeds the melting temperature of the insulating sheet. Current flow between the resistive body and the control body is detected to trigger a power cutoff to the resistive body. The material of the insulating sheet is selected to have a melting point well below an ignition temperature of the materials in the heating body, thereby triggering power cutoff at temperatures low enough to prevent fire. A control system normally controls the temperature of the heating body between an upper and a lower limit.

대표청구항 ▼

A heating body comprising: a resistive body; a flame-resistant sheet; an insulating sheet; said resistive body being inter-imposed between said flame resistant sheet and said insulating sheet; said flame resistant sheet, resistive body, and insulating sheet forming a layered structure; a control bod

A heating body comprising: a resistive body; a flame-resistant sheet; an insulating sheet; said resistive body being inter-imposed between said flame resistant sheet and said insulating sheet; said flame resistant sheet, resistive body, and insulating sheet forming a layered structure; a control body on an upper surface of said layered structure; at least one heat-sensing wire attached to a lower surface of said layered structure; means for connecting a power source to said resistive body; means for connecting said power source to said heat-sensing wire; and means for controlling a power applied by said power source to said heating body; said means for controlling power comprises: a temperature control system; and means for shutting Off a current flowing between said power source and said heating body; said means for shutting off said current comprises: an after effect rectifying circuit having means for rectifying and a relay coil; said relay coil being in an open position and having holding contacts for holding a closed position; said rectifying means receiving an input of leaked current from said control body; a first latching relay connected between said output of said control switch and said resistive body; said first latching relay having a closed position during operation of said power source and having an open position during a shutoff condition; means for connecting said first latching relay to said resistive body; a second latching relay, connected between said power source and said resistive body and said heat-sensing wires; said second latching relay having a closed position during operation of said power source and having an open position during a shutoff condition; said relay coil being mechanically connected to said first and second latching relays; a reference voltage generating circuit; said reference voltage generating circuit receiving an input from said power source and producing a voltage-regulated output; said voltage-regulated output being applied to said after effect rectifying circuit thereby producing a rectified output; a control terminal having first and second inputs; said first input receiving said rectified output from said after effect rectifying circuit; and said second input receiving said input of leaked current from said control body, whereby a presence of said leaked current from said control body closes said relay coil holding contacts, thereby moving said first and second latching relays to said open positions, whereby said input of leaked current from said control body along with said voltage-regulated output produce a signal to said rectifying means to apply an energizing signal across said relay coil whereby said relay coil closes said holding contacts and signals to said first and second latching relays to said respective open positions to shut off power to said resistive body.