Proximity Sensor Height Control for Permanent Wheelchair Lifts

The patent replaces mechanical contact sensors with optical sensors that detect platform height without physical contact. The optical sensor system uses light beams to measure the position of the lift car relative to the stage, eliminating the need for mechanical contact while maintaining detection accuracy. This substitution enables permanent installation where mechanical contact would be impractical or damaging.

The patent implements a self-adjusting height control system where the optical sensor automatically detects when the lift car is at the correct height relative to the stage. During installation, the system self-calibrates by detecting the relationship between the lift car and stage positions, eliminating the need for complex manual measurements and adjustments by installers. The system maintains precise height settings through automatic feedback control.

The patent uses optical sensors to provide feedback on gate position and lift car height to the control system. The sensors detect whether gates are properly closed and whether the lift car is at safe positions, automatically preventing platform elevation when safety conditions are not met. This feedback-based approach implements reliable safety features through relatively simple sensor-input/control-response logic rather than complex mechanical safety mechanisms.