Looks like a New Britain derivative mechanism. Standard traps to be avoided (flip spring in right way, don't pinch finger when reassembling with the little E-clip) and detent ball was stuck and then the spring was toast. Replaced the spring and reassembled with lube - good as new.
It seems that Stanley Tools absorbed the NB design - alot of their ratchets use it. I've seen some Blackhawk, Pro America, Proto, Matco BR8N, that are the same. So, someone needing a kit for this one could probably insert one of the other (available) kits, and it would drop right in. 45 teeth in the head, 9 teeth on the pawl.