LIFTING AND CARRYING DEVICE FOR HEAVYWEIGHT OBJECT

摘要

PURPOSE:To equalize weight distribution among jacks by comparing detected distances between ultrasonic transmitters and receivers with a reference value and making judgement on the comparisons, and by controlling each of the jacks in accordance with the results of the judgements. CONSTITUTION:A control circuit 17, actuated by a timing signal from a pulse oscillating circuit 16, drives an ultrasonic transmitter 14 attached to a jack 1. The transmitted ultrasonic wave is received by an ultrasonic receiver 15, and the received signal is inputted to a distance detecting circuit 18 through the circuit 17. Then a measurement is made on an interval between the rises of the sending and receiving waves, and thereby a distance between a transmitting element S1 and a receiving element S2, placed facing each other, is detected. The distance detected for the jack 1 is made to be a reference, and distance detected for other jacks 2-4 are respectively compared with the reference value. When the result of any one of the comparisons proved to be longer than the standard measurement, it is judged that the concerned jack is lifted too much, and when the result was shorter than the standard measurement, the concerned jack is judged to be downed to much. Following similar procedures, heights of the jacks 2-4 can be controlled in accordance with the results of the judgements.