Let me know if you need any more detail. I guess these unit are
comparable to the swiss Eckold units shown in Fournier. They were not
cheap compared to the ones commonly available.

http://metalworking.com/DropBox/dfsshrink.txt
http://metalworking.com/DropBox/dfsshrinkpatentpic.jpg
http://metalworking.com/DropBox/dfsshrinkside.jpg
http://metalworking.com/DropBox/dfsshrinktop.jpg

From the ideas shown it may be possible to improve the cheaper ones to
include this type of preload device. As you have a set you could see
what you reckon. I can dig out the rest of the patent if required and
post the angles given for the wedge and preload spring force tomorrow.

Bill Chernoff wrote:

Photos would be great. I'll also take some of mine for interest's sake.

Bill