In Magic the Gathering, if you have multiple Dragon's Claw artifacts do you gain multiple life for red spells?

This issue seems to apply to many things. Does a Brood Sliver give multiple tokens for damage if you have more than one Brood Sliver? What about The Rack? It came up in a game where one player had 3 Dragon's Claw artifacts out and thought he should gain 3 life for each red spell and his opponent felt that the ability would trigger only once regardless of the number of Dragon's Claws out. Thanks!

Indeed he gets 3 life from 3 dragon's claws. Same goes for the rack. If it triggers like that, it can be stacked multiple times. If you have to pay mana for it, it'll happen once per payment.

Final Fantasy VII: New magic materia and spells