EE WAS TIGHTENING TIE DOWN STRAP WITH HAND WINCH. STRAP BROKE AND HIS HAND SLIPPED & STRUCK WINCH MOUNT FRAME. X-RAY SHOWED HAIRLINE FRACTURE OF 2ND METACARPAL BONE OF RT. HAND. WRIST SPLINT W AS PRESCRIBED AND EE WAS PLACED ON RESTRICTED DUTY. NO LOST TIME.