Which component is described as the 'heart of the mechanism' that translates vertical push into locking movement?
Answer
The Cam/Ratchet
The cam or ratchet is a shaped component critical for translating the vertical action of the plunger into the rotational or locking movement necessary to engage or disengage the cartridge holder.

#Videos
How Does a Clicky Pen Work? - YouTube
How a Retractable Ballpoint Pen Works - YouTube
Related Questions
What activates the extension and retraction of the writing point in a click pen?Which component is described as the 'heart of the mechanism' that translates vertical push into locking movement?What feature gives the click mechanism an appeal compared to a silent twist-action pen?What is a significant trade-off in tip protection when comparing a click pen to a capped pen?What is the primary indicator that the internal tolerances of a click pen mechanism are wearing down over time?What occurs immediately upon the first press of the button to extend the pen?Why is standard ballpoint (oil-based) ink commonly used in click pens for fast note-taking?Why is the click action favored over a simple cap for promotional pens?What is the engineering goal for high-end writing tools compared to disposable clickers?What modular benefit often comes with owning a well-designed click pen?