Dear Frans ;
I seriously doubt that anyone can arrange such a thing as concealing patents, as the rule of patents is that your invention is protected for 20 years (as long as you pay), but publicly disclosed one year after you took the patent.
For old patents, you should consult this page :
I had a 1905 patent copy issued last year for a friend of mine. There were absolutely no problem, as long as you pay for the copy...
It is also possible to consult the documents on site :
I think that if you can find your patents there, the scans they provide you are quite good quality.