[Lhundulinwen]

Though Aragorn was an excellant fighter, he needed some type of weapon with him. Even though the broken sword was more of a calling card, or more like a good guy flashing the really big gun, Aragorn would have an assortment of weapons. Probably a sword, a knife, and bow and arrow, and possibly some kind of hidden weapon. I personally think Gandalf had already told him a long time before the hobbits set out to patrol the Shire. On the far side of the Shire, he was sidetracked, and Gandalf couldn't get a hold of him. He may not have had the broken sword with him while circleing the Shire, but he had it in a safe spot. But that's just my theory.