GIBSONIA, Pa. - A wood-chipper being hauled by a dump truck broke free and bounced across a highway, striking a minivan and killing a father and two of his young triplets, police said.The dump truck was traveling north when the wood-chipper broke free around 5 p.m. Thursday and crossed the center line of Route 8, a busy highway that snakes through Pittsburgh's northern suburbs. The chipper, which police estimate weighed about 5,000 pounds, then hit the south-bound minivan. - AP