(under subclass 690) Mattress including means to change the supporting characteristics of the mattress as a whole from stiffer to less stiffer modes and vice versa.
(1) Note. The means to change the firmness of the mattress generally include means such as tightenable lacings or strings that crisscross the mattress, or means that are used to loosen or tighten the support characteristics of springs within the mattress.
(2) Note. Excluded from this subclass are gas filled mattresses that could have their firmness changed by increasing or decreasing the gas pressure, reinforced mattresses that have a rigid layer or plate within them, and mattresses that have a plurality of sections of different firmnesses.
SEE OR SEARCH THIS CLASS, SUBCLASS:
701, for reinforced mattresses that have a rigid layer of plate.
706+, for gas containing mattresses.
727+, for mattresses that have a plurality of sections of different firmnesses. 936, for devices that have springs of variable or adjustable support characteristics.
SEE OR SEARCH CLASS
267, Spring Devices,
177, for a coil spring including an adjustable end thrust member to vary the thrust reaction.
