A claw assembly includes a collar, claws and a synchronizer. The collar includes slots. The claws are pivotally connected to the collar. Each of the claws includes a protuberance extending into the collar via one of the slots. The protuberances are movable along the slots. The synchronizer includes a receiving portion for receiving the protuberances. The receiving portion of the synchronizer is movable in the collar between an opening position and a closing position. The synchronizer opens the claws by the protuberances in the opening position. The synchronizer closes the claws by the protuberances in the closing position.