Patent ID: 8096183

Claim:
A method for determining a height of objects disposed on a conveying device, wherein an ultrasonic sensor positioned in relation to the conveying device transmits repetitively ultrasonic pulses directed toward the conveying device and any detectable objects disposed thereon, and the ultrasonic pulses are reflected from a surface of the conveying device or surfaces of the detectable objects and are detected by the ultrasonic sensor, wherein delay times of the ultrasonic pulses are determined from moments of transmission and moments of detection of the ultrasonic pulses, and a height of an object surface relative to the surface of the conveying device is determined from the delay times of the ultrasonic pulses reflected from an object surface, wherein the delay time of the ultrasonic pulses reflected from the surface of the conveying device is stored as a reference value, when there is an increase in the measured delay time from a lower to a higher value, the higher value is stored and used as a new reference value, when there is a decrease in the measured delay time from a higher to a lower value, the lower value is interpreted as the delay time value of ultrasonic pulses reflected from an object surface, and the height of the object surface relative to the surface of the conveying device is determined from a difference between a most recently stored reference value and a delay time value relevant to an object surface.