Image Number 2 for United States Patent #4843664.
The invention disclosed is a portable thermally insulating mattress. The mattress comprises body support means and waterproof enclosure means. The body support means is in the form of a honeycomb structure which is incompressible in a vertical direction under body weight, while being compressible in a horizontal direction to facilitate packing. The cells of the honeycomb structure are sized to balance the heat loss by radiation with the heat gain by conduction by the air in the cells, i.e. 5-15 mm mean diameter for a 5 cm thick mattress.