If you have an old shoe patcher and you are looking for the manual give this link a try: www.altenaehmaschine.de .
Click on "Bedienungsanleitungen" and it will show on the left side which ones are there to view; currently there's Adler Class 30, Singer 29K, Duerkopp and Claes.
Yes, the site is in German, as are the Manuals, but even if you can't read them or find an old Kraut like me to translate them for you the pictures can sometimes help you out just by themselves. I had been looking for a