Abstract: A plunger for a matrix mattress includes a pin guide having a flange and a guide body extending from the flange. A pin slidably received within the pin guide includes a flange located above the flange of the pin guide and a shaft extending from the flange through the guide body. The flange of the pin carries a deformable head. A tension spring has a first end fixed to the guide body and a second end located below the guide body positioned to receive a bottom end of the pin shaft. The spring is configured to resiliently stretch with downward motion of the pin with respect to the pin guide. A dampening device captured around the shaft of the pin between the flange of the pin and the flange of the pin guide resiliently deforms with downward motion of the pin with respect to the pin guide.

Abstract: A bed plane with improved structure, comprising a plurality of slats, arranged transversally to the frame (10) of the bed and connected to it through slat-holders, includes a series of stems or pistons (11), each connected with one or more of the aforementioned slats and associated with a respective spring (12) for vertical sliding; each piston carries a pulley or sliding guide (15) for the transmission of motion, which occurs thanks to flexible members (16), such as cords, belts, chains and cables, fixed to the frame (10) of the bed plane. The pistons (11), connected to the slats, react to the pressures exerted by the body lying down on the bed plane, compensating for the sinking created by the heaviest parts of the body, i.e. those parts between the shoulders and the pelvis, with an upward thrust, supporting the lighter parts, in other words the back and kidneys.