QFB was set very shortly after ToD because Ratchet was desperate to find his buddy, Clank. Same goes with ACiT, because they are both direct sequels and it all happens in less than a year. You haave probably heard that QFB was Released 1 year after ToD and same with ACiT.
EDIT BY DROPHYD167b: Actually, there is a year between each game, as evidenced by Qwark's recap at the start of ACiT. Plus, it was clearly stated that QfB took place a year after ToD.