| 摘要 |
In a bed having a number of springs between the mattress and the spring support board, a piping for air circulation is provided underneath the spring support board to communicate with space for the spring through the holes provided in the board for the inlet and outlet of the pipe. an incandescent electric lamp is provided in the pipe on the outlet bend to furnish heat through convection and circulation of air. The heat supplied keeps the mattress warm for the comfort of the user.
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