Many types of equipment involve inclinable table surfaces. Industrial operations often require objects to be tilted or elevated, and hospital equipment must frequently be capable of supporting a patient in an inclined position. Considerable weight may have to be supported in both cases, which has led to power-actuated systems subject to the control of an operator. Air (pneumatic) and liquid (hydraulic) systems for actuating and positioning the moveable table surface are frequently used, depending on the requirements of the particular application. A general term covering both systems would be "fluid"-operated. Compressed air provides quicker action, and less leakage problem, but is compressible. Hydraulic operation is therefore more appropriate where positive positioning by the actuator alone is required. The greater simplicity of the pneumatic system provides an inducement to include some sort of positive positioning for the air-operated actuator. The addition of fail-safe characteristics also increases the number of applications that can utilize the advantage of the pneumatic system. Rupture of an air conduit or air bag actuator is then no longer a hazard.
USPTO Backgrounds
USPTO Backgrounds