I was contacted by Madelaine with a problem she was having with removing her swing door so her builder could lay a new floor. I am happy to show I was able to help.
The "Zephyr" was introduced in 1953 by WILLIAM NEWMAN AND SONS Ltd and is in this instance is a hold open type, Madelaine's "Zephyr" however was manufactured in 1966 I believe from seeing this stamped into the top plate.
The floor spring appears to be approximately two thirds of the width of the 400 that I have shown you on many occasions.
It is in someways similar to Joseph Bardsleys floor spring in so much as it has a central piston encased by a single spring.