Crane warning system

Claim 1

IN MATERIAL HANDLING EQUIPMENT HAVING A BOOM PIVOTALLY MOUNTED ON A SUBSTANTIALLY HORIZONTAL RELATIVELY STATIONARY STRUCTURE FOR ELEVATION, DEPRESSION, AND HORIZONTAL SLEWING AND CAPABLE OF SUSPENDING WEIGHTS OF VARIOUS MAGNITUDES FROM THE FREE END THEREOF, SAID BOOM BEING MOVABLE TO ASSUME AN INFINITE NUMBER OF INCLINED POSITIONS IN A VERTICAL PLANE BETWEEN POSITIONS OF MAXIMUM DEPRESSION AND MAXIMUM ELEVATION AND TO ASSUME AN INFINITE NUMBER OF POSITIONS IN A HORIZONTAL PLANE WITH REFERENCE TO THE HORIZONTAL LONGITUDINAL AXIS OF SAID SUPPORTING STRUCTURE, A MOMENT COMPUTING AND INDICATING SYSTEM FOR CONTINUOUSLY COMPUTING AND INDICATING A PLURALITY OF MOMENTS AFFECTING THE EQUIPMENT COMPRISING A SOURCE OF ELECTRICAL POWER, A COMPUTER INCLUDING A LOAD TRANSDUCER RESPONSIVE TO THE LOAD ON THE BOOM AND CONNECTED ACROSS SAID SOURCE OF POWER, SAID COMPUTER FURTHER INCLUDING A COSINE POTENTIOMETER MECHANICALLY CONNECTED TO THE BOOM FOR ADJUSTMENT IN ACCORDANCE WITH THE VERTICAL ANGULAR ATTITUDE OF SAID BOOM AND ELECTRICALLY CONNECTED TO THE OUTPUT OF SAID LOAD TRANSDUCER, A SINE-COSINE POTENTIOMETER MECHANICALLY CONNECTED TO SAID BOOM FOR ADJUSTMENT IN ACCORDANCE WITH THE HORIZONTAL SLEWING ANGLE OF SAID BOOM WITH RELATION TO SAID STRUCTURE AND CONNECTED IN SERIES WITH SAID COSINE POTENTIOMETER, MEANS ELECTRICALLY CONNECTED TO THE OUTPUTS OF SAID LOAD TRANSDUCER AND SAID SERIES CONNECTED POTENTIOMETERS FOR PRODUCING OUTPUT SIGNALS HAVING MAGNITUDES PROPORTIONAL TO THE MOMENTS CREATED BY THE VARIOUS LOADS ON THE EQUIPMENT, MEANS FOR VISUALLY INDICATING THE MAGNITUDES OF SAID SIGNALS AND MEANS FOR AUDIBLE INDICATION WHEN ANY ONE OF SAID PLURALITY OF MOMENTS EXCEEDS A PREDETERMINED FRACTION OF THAT MAXIMUM MOMENT WHICH WOULD CAUSE SAID EQUIPMENT TO OVERTURN.