Modern umbrellas have a rider (a hollow cylinder) that slides up the shaft to force the umbrella vanes open. It is held in place by a spring latch that protrudes close to the top of the shaft - I've seen it called the 'top spring'.
How early was this convenience widely manufactured? Was there some other locking mechanism used before that (e.g. friction, a bolt/screw, etc.)?
I've tried looking for images of antique umbrellas but it's hard to determine the age of the umbrellas pictured, and most of them don't show the upper part of the shaft.
[I'm reading an old passage in a foreign language describing the locking mechanism and the exact details are important for understanding the entire discussion therein].