The CHK and FOUND elements are the results of checkdisk having run to clear-up file system anomalies or corruption (such as can occur with premature removal of a USB drive). Unfortunately such a clean up is counter productive to recovering data and should never be run when data loss is a possibility.
You could try scanning the drive with GetDataBack for FAT which is about your best shot. The scanning is free and you can open any such recovered files one by one for free but must buy to copy them all in one go. Good luck and I think you will need it to have much success.
I have presumed this is a FAT partition. Most USB drives are FAT and these found elements are typical of corrupted FAT folders which are not as resilient as NTFS folders - especially when in the root of the drive. A sub-folder in another folder is more likely to be findable but under FAT there is no folder hierachy in the root of a partition. Possibly the second morrored FAT table might find the lost elements and if so GDB might work.