It sure looks like a Ritchie key; perhaps it is a different model lock? I agree it looks like a different lock from the one in the patent image. Thank you for the detailed description of the mechanism. I appreciate it. I'll take a look through the older patents as time allows and see if I can come up with any other suggestions. Thanks for sharing the pictures of the lock repair and key repair. It's a shame you didn't get the chance to repair the key; the other one you did looks nice. Thanks for asking for me if it was for sale. If you happen to come across anything else you think I'd be interested in, please keep me in mind, and I'll keep you in mind if I come across anything needing repair. I'll let you know if I find anything else that would be helpful in identifying it more directly.