Caterpillar’s second-quarter profit jumped 67 percent and it’s optimistic about the future, but a weaker global economy may still pose challenges for the equipment maker.

Many countries in Europe are in recession or teetering near it, a pending budget crisis could send the U.S. back into recession and China’s growth is slackening. A worldwide slowdown would make it harder for Caterpillar to meet its 2012 goals. Still, the company remains confident the economy will get better next year. “We’re not playing for an implosion,” said CEO Doug Oberhelman. “We’re playing for growth.”

Others were more wary. “It was a good solid quarter, but there are still questions out there from a global economic standpoint, and that causes some cautiousness,” Edward Jones analyst Jeff Windau said.