Short answers, pulled from the story.
A metal rod connects the top cymbal to the foot pedal in every standard hi-hat setup. The bottom cymbal remains fixed while the upper one moves downward when a drummer presses the pedal.
A standard size emerged around 1926 when Barney Walberg developed raised models playable by hand and foot. Kaiser Marshall and Papa Jo Jones appear in editor notes as potential inventors alongside Walberg.
Barney Walberg founded the drum accessory company Walberg and Auge where he likely created early hi-hat prototypes. Kaiser Marshall also appears in historical records as someone thought to have invented the modern design.
Gently pressing the pedal creates very quiet chick sounds suitable for soft ballad accompaniment. Striking fully open hats hard produces loud volumes used in heavy metal music songs.
Rock, pop, jazz, and blues styles all rely on the standard drum kit configuration today. Jazz bands adopted the swing-pulse focus pioneered by Papa Jo Jones in the mid-20th century.