An employee was helping a three-man crew with a backhoe to lift a walk-behind saw approximately 6 inches and move it forward approximately 3 feet. The employee attached rigging from the walk-behind saw to the backhoe and stood to the side of the forks approximately 4 feet away. As the backhoe operator lifted the saw, the backhoe forks disengaged and struck the employee's hard hat. The employee was hospitalized for a head injury.