Abstract: An alternating pressure pad (1) comprises inflatable cells (9,10) supplied with air by supply lines (7, 8) from a compressor (2) via supply line (3). A pressure controller controls the output of the compressor. Also connected to supply line (3) is an angle detection valve (40) restricting flow of air to atmosphere with increase in its angular position and a pressure transducer (17). Any increase in pressure due to an increase in angle of the detection valve (19) results in back pressure in the detection line. The pressure controller (2) uses the pressure transducer (17) to detect this change in pressure and then acts to adjust compressor output to the cells (9, 10) accordingly. The angle detection valve (40) is positioned under the head section of the pad to move with the head rest section.

Abstract: An alternating pressure pad (1) comprises inflatable cells (9,10) supplied with air by supply lines (7, 8) from a compressor (2) via supply line (3). A pressure controller controls the output of the compressor. Also connected to supply line (3) is an angle detection valve (40) restricting flow of air to atmosphere with increase in its angular position and a pressure transducer (17). Any increase in pressure due to an increase in angle of the detection valve (19) results in back pressure in the detection line. The pressure controller (2) uses the pressure transducer (17) to detect this change in pressure and then acts to adjust compressor output to the cells (9, 10) accordingly. The angle detection valve (40) is positioned under the head section of the pad to move with the head rest section.

Abstract: An alternating pad comprises a first set and a second set of alternately inflatable cells. Both sets of inflatable cells are supplied with air from a pump via a rotary valve. A sensor is positioned under the pad to receive pressure exerted by a patient upon movement and to be compressible relative to the applied pressure. Any change in patient position or movement will cause an alteration in the airflow in the sensor pad tube and will reduce or increase the differential pressure measured at the pressure transducer. Based on this feedback the microprocessor directly controls the power level to the pump and increases or decreases the air flow to the cells to alter the amplitude of the cells and also controls the timing of the rotary valve to change the timing of the inflation and deflation cycle.