US Patent 8146702 Load handling bumper for material handling device

A material handling device includes an automated guided vehicle configured for use with a carrier. Both the vehicle and the carrier include a bumper having a reflective target mounted thereon. The automated guided vehicle includes a sensor having a light source and a scanner for receiving a reflection from the light source. The light source directs a first light beam at the vehicle reflective target and a second light beam at the carrier reflective target. When the vehicle bumper is moved toward the sensor, the vehicle reflective target moves into a reflective position and when the carrier bumper is moved toward the sensor, the carrier reflective target moves into a reflective position. The movement of the either bumper into the reflective position generates a signal from the sensor to a controller to control the movement of the automated guided vehicle in response to movement of either bumper.