Why the Zippo Lighter?
I'm not a smoker. But I am an engineer. And the Zippo lighter has been mentioned countless times as the gold standard for a bi-stable mechanism. The lid flings open and makes a memorable "clink" sound. What is a bi-stable mechanism? We'll get into that soon.
The Zippo dates back to the 1930's! And as far as I can tell, the design has hardly changed. By my disassemby, there are more than 20 parts, including all the rivets.
What Is A Bi-Stable Mechanism?
They are everywhere. Light switches, earbud cases, old slider phones. Bi-stable refers to something that has two stable states. In this case the lid is stable when it is closed and open. But everywhere in between, it is not stable.
Let's walk through the different states.
OPEN
FLIP
CLOSED
OPEN
FLIP
CLOSED
Let's Open Up The Lighter
To understand how the lighter works, let's take it apart to see what's inside
Let's get to know the Cam a bit better.
A Cam is a classic mechanical component used in countless mechanisms. In this design, it's crucial in helping the Lid flip open and flip closed.
This pear shape is critical to the Cam's function
Cam rotates about this hole.
Let's look at the Bi-Stable Lid Mechanism
Let's walk through the lid mechanism, step by step, to understand how it all works
