INJURED WAS ATTEMPTING TO CANGE A BROKEN SPRING ON A RUBBER TIRED MANTRIP. HE RAISED THE MANTRIP WITH A FORKLIFT & WHEN HE WAS LOOSENING THE SPRING BOLTS, THE MANTRIP TEETERED & THE END DROPPED CATCHING INJURED'S RIGHT HAND BETWEEN THE IMPACT WRENCH AND THE GROUND. WHEN HE PULLED HIS HAND FREE, HE LACERATED THE BASE OF THE MIDDLE FINGER. TRANSPORTED TO ER & RECEIVED 7 STITCHES.