An employee was using a manipulator/hoist to lift a mower deck off an assembly table when the mower blade became caught on an attachment on the table. The table then lifted with the blade as the deck was rising. The employee went to push the table back down and release it from the blade. At the same time, the controls were activated to lower the manipulator/hoist. The employee's left thumb was then pinched between the table and the manipulator/hoist, amputating the distal portion of the thumb just below the nail.