Angle detection and control

A pressure control system for an inflatable patient support, the system including an angle detection valve having:

• a. a valve input end into which fluid is supplied;
• b. a valve output end from which the fluid exits;
• c. a valve element configured to move via the force of gravity from:
• (1) a non-obstructing position wherein the valve element allows the fluid to flow through the valve output end, and
• (2) an obstructing position wherein the valve element at least substantially blocks the fluid from flowing through the valve output end,
• when the angle detection valve's angular orientation is changed from a first angle to a second angle.

The pressure control system of claim 10 further including:

• a. a first inflatable cell:
• (1) tiltable to different angular orientations, and
• (2) wherein the angle detection valve is mounted to tilt with the first inflatable cell;
• b. a pressure transducer configured to obtain pressure measurements dependent on the fluid pressure at the valve input end, wherein the fluid pressure in the first inflatable cell is adjusted in response to the pressure measurements.

The pressure control system of claim 10 further including:

• a. an inflatable cell,
• b. a pump supplying fluid to the inflatable cell and to the valve input end, wherein:
• (1) fluid supplied to the inflatable cell is not also supplied to the valve input end, and
• (2) fluid supplied to the valve input end is not also supplied to the inflatable cell.

A pressure control system for a patient support, the system including:

• a. an angle detection valve having a valve element moving between:
• (1) an obstructing position wherein the valve element at least substantially prevents fluid flow within the angle detection valve, and
• (2) a non-obstructing position wherein the valve element allows fluid flow within the angle detection valve,
• in dependence on the angle detection valve's angular orientation;
• b. a valve supply line between the angle detection valve and a source of pressurized fluid, and
• c. an inflatable cell, wherein the fluid pressure within the cell is varied in dependence on the fluid pressure in the valve supply line.