In my 1925 Parker, Winder & Achurch vintage trade catalogue the next floor spring I will show you is advertised as The "Leader" Patent Floor Spring with hydraulic check. Having a square pin and somewhat of an overly complicated mechanism this floor spring was repaired for Knowle Parish Church. You can clearly see the square pin in the first photograph and in the later advert from Wm Newmans & Sons Ltd, describing it as the Britannic.
As you can see however from the 1961 patent, changes were made to the Leader/Britannic. These changes simplified the pin to spring transfer mechanism, the cover plate was slightly reshaped and the pin itself was changed to a more rectangular design.
After stripping the Leader/Britannic down, rebuilding and manufacturing a new pin our clients have a set of floor springs to be proud of!
As there is so little information out there with regard to door closers, especially vintage and antique model floor springs, I thought I would start this blog.