RC60forklift lifting 1/4"" steel plate 5'x13'with grab claw & 1/4"" chain. C-clamp used to keep chain from slipping. Plate needed flipped end for end. When turning C-clamp came loose causing it to fall. Another ee clear, but ee pushed forcefully to ground in awkward manner. Plate rested partially across him. Another ee able to remove & get help.