The evolution of a clock is one of the most impressive stories in the history of human kind. Well, it is actually not know who invented the first one. Probably the first one are the sun clocks.
When we go forward, than the weigh-driven and mechanical clocks were invented. Here is the situation the same, not sure who was the first inventor but we can attribute, based on some sources, the first weight-driven clock to Pacificus in 9th century and Gerbert for the invention of a mechanical clock.
Today, most of clocks are produced by a big companies, whether they are mechanical or electronic. Even the technology has changed, one thing remains the same, clocks are for measuring something that we call time.