초록 ▼

A heater adapted for placement under the mattress of a waterbed consists of a flexible laminated pad having an upper layer of resistive elements embedded in electrical insulating material, and several subjacent layers of heat-reflective and thermal insulating materials. All of the layers are encased

A heater adapted for placement under the mattress of a waterbed consists of a flexible laminated pad having an upper layer of resistive elements embedded in electrical insulating material, and several subjacent layers of heat-reflective and thermal insulating materials. All of the layers are encased in a protective waterproof sheath. The pad may be connected in parallel with one or more similar pads and a heat sensor may be associated with each pad. In one embodiment, a control circuit is provided for supplying power to all of the pads simultaneously when all of the heat sensors detect that the temperature of the mattress has dropped below a predetermined value. In another embodiment, power may be supplied to each pad independently of the other pads.

대표청구항 ▼

A heating unit for placement under the mattress of a waterbed, said unit comprising: a plurality of heating pads electrically interconnected in parallel with one another; a plurality of heat sensors, one heat sensor associated with each heating pad, said sensors being electrically interconnected in

A heating unit for placement under the mattress of a waterbed, said unit comprising: a plurality of heating pads electrically interconnected in parallel with one another; a plurality of heat sensors, one heat sensor associated with each heating pad, said sensors being electrically interconnected in series with one another; a switch means connected in parallel to said heating pads, said switch means applying voltage to said heating pads when closed; a thermostat connected in series to said heat sensors, said thermostat controlling energization of said switch means; and a plurality of lead wires connecting said pads and said sensors to said thermostat and a power supply; whereby electrical power is supplied to said heating pads only when all of said sensors detect that the temperature of the waterbed mattress has dropped below a predetermined value.