Gyrating screen

Claim 1

A GYRATING SCREEN MACHINE COMPRISING, A BASE, AN INCLINED SCREEN BODY HAVING A SCREENING SURFACE, A HEAD END, AND A DISCHARGE END, MEANS LOCATED WHOLLY BELOW SAID BODY FOR IMPARTING GYRATORY MOVEMENT THERETO, COMPRISING A DRIVEN SHAFT, A BALANCE WHEEL FIXED TO SAID SHAFT, A CRANK ON SAID BALANCE WHEEL AND DRIVE BEARING CONNECTING SAID CRANK TO SAID BODY, SAID DRIVE BEARING CONSTITUTING A SUPPORT FOR SAID HEAD END, A SUPPORTING FRAME COMPRISING A PAIR OF POSTS AT EACH END OF SAID BODY, SAID MOVEMENT IMPARTING MEANS BEING CARRIED BY SAID PAIR OF POSTS AT SAID HEAD END, A PAIR OF STABILIZING STRUTS FOR SAID HEAD END, EACH EXTENDING SUBSTANTIALLY PERPENDICULARLY DOWNWARD FROM SAID BODY, EACH SAID STRUT HAVING A LOWER END AND AN UPPER END, A SEAT FOR THE LOWER END OF EACH OF SAID STRUT, MOUNTED ON SAID BASE, A SEAT FOR THE UPPER END OF EACH SAID STRUT, MOUNTED ON SAID BODY, A RESILIENT CUSHION CARRIED BY EACH SAID END OF EACH SAID STRUT, A SUCHION BEING INTERPOSED BETWEEN ONE SAID STRUT END AND ONE SAID SEAT FOR EACH STRUT, SAID SEAT FOR SAID LOWER END OF EACH SAID SUPPORTING STRUT BEING ADJUSTABLE RELATIVELY TO SAID BASE TO VARY THE ANGULARITY OF EACH SAID STRUT RELATIVELY TO SAID BASE, SAID SUPPORTING FRAME BEING WHOLLY LOCATED BELOW SAID TOP SCREENING SURFACE WHEREBY SAID SURFACE IS UNOBSTRUCTED, A MAIN COUNTERWEIGHT CARRIED BY SAID BALANCE WHEEL, A COMPENSATING COUNTERWEIGHT MOUNTED FOR REVOLUTION ABOUT THE AXIS OF SAID SHAFT AND HAVING A SMALLER CIRCUMFERENCE OF REVOLUTION THAN THAT OF SAID MAIN COUNTERWEIGHT, AND GEAR MEANS CONNECTED TO SAID SHAFT FOR DRIVING SAID COMPENSATING COUNTERWEIGHT IN A DIRECTION OPPOSITE TO THE DIRECTION OF ROTATION OF SAID SHAFT AND MAIN COUNTERWEIGHT.