Doug, Thanks for your follow-up. It would be interesting to see if the British Patent has any drawings or other details. Since I posted the thread, I found what may be the original patent, also 5661, but registered in Germany to Friedrich Sengpiel, dated Nov. 17, 1878 for a “Resilient Keyhole Cover”. There are no drawings or illustrations, just a brief paragraph describing the advantages of a springloaded dust cover. The interesting sidebar may be that while we are referring to the padlock in question as a “F. Sengpiel Patent Padlock”, the phrase itself may refer only to the dust cover and not the padlock. The brief description accompanying the patent makes no mention of the padlock per se. Naturally, if you invent a padlock dust cover you have a lock in mind - but perhaps not a particular model padlock. In other words, the padlock models we have found may have been made, and perhaps patented – by an entirely different enterprise sometime after 1878.
The German Patent Office deserves the credit for finding the 1878 German Patent and after two weeks of give and take with them it is apparent there is no more information, other than what I mention below, available under the “F Sengpiel” name. They did find 3 patents applied for under the names Friedrich and Oscar Sengpiel, dated 1883, and these were for a “Lockable Key Holder” - but absolutely no more detail than the titles.
A prominent German lock collector who uses the name Peter Schnurzel (his real name is much longer and German) referred me to the Velpert (Germany) Lock Museum but, so far, this has yielded no results.
So, we keep digging.
Gordon
