An employee was observing a piece of wood being winched into the infeed chute on the wood chipper. As the wood contacted the bottom edge of the chute it become stuck. The employee grabbed the winch and the piece of wood to clear the bottom of chute so it could be winched further into the chute. The wood rotated sideways and pinned his leg between the wood and the infeed chute of the chipper, resulting in a fractured right femur.