This present invention decreases the risks of pressure ulcer formation by steadily and smoothly changing the support points of the body to vary the effective area of support of bony protrusions from the body on the skin and compressing it to the bed, which causes the reduction, as close to zero as possible, of the amount of time pressure is exerted by the weight of the body on the bed and restricted areas of support, preventing that the areas of risk of low blood flood by the weight of the body, remain in ischemia and, therefore, with increased blood flow to these parts of the body.The purpose of this present invention is designed to slowly, steadily, and smoothly change the body support points to vary the effective area of body support on the bed with slow, constant oscillations, in the directions of the width and length of the mattress support and having two sets of drive systems (DS) attached to the chassis (4) intended to support all components, such as the electric motor (7), driven by a power drive (PWM) in the control panel (PC), said electric motor (7) being fitted with gear (8) connected to another gear (9) and a minimum pitch (10), which drives the worm thread vertical shaft (11) intended to move the flat or arched mattress support (2) vertically and the coupling (13) that carries out the vertical coupling of the tip (12) of the vertical shaft (11), which allows adjustment of the coupling (13) and tip (12) of the vertical shaft (11) to the lateral movements between the tip (12) of the vertical shaft (11) and the flat or arched mattress support (2) resulting from transversal oscillations； the rotation shaft (5A) support (5), which couples with the cylindrical shaft (3) attached to the arched mattress support (2), the equipment's chassis (4), and the noise and vibration absorbing cushions (6) as well as the support (14) of hoods (15) and (16) that surround and protect the vertical screw shaft (11).
