Quick change units and add-on units thereof for earth-moving and building machines and also for earthworking equipment, loading equipment, lifting equipment and other multi-purpose equipment of this kind, including excavator shovels, rear excavator shovels, back-acter shovels, shovel buckets, rock back-acter shovels, trapezoidal buckets, breaking back-acter shovels, ditch-cleaning shovels, ditch-profiling shovels, drainage shovels, ejector shovels, swing shovels, grabs, hammer tools, scrap shears, boring equipment, demolition equipment, concrete-clearing equipment, demolition posts, rock-grappling tongs, lever equipment, breaking teeth and grubbing equipment