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Free Body Diagram

I sketched a free-body diagram of a hot glue gun’s stick-advance mechanism in an attempt to formalize its action. (I was also surprised to see hot glue used to secure wires inside the hot glue gun… a textbook chicken / egg paradox.)

April 1 2010 at 2 PM

Neal:

Very nice diagram. I think it merits a followup post. This diagram ignores the complex interaction between the glue stick and L3. In my opinion, that is the most interesting part of the system -- the whole reason why has four moving parts instead of three.

When the user presses the trigger, L3 rotates counter-clockwise and its friction with the glue stick increases until they move as a single unit. When the user releases, the spring pushes and L3 rotates clockwise, decreasing friction and allowing it to slip. Why does friction increase CCW and decrease CW?

June 13 2013 at 1 PM

shane:

probably got something to do with its pivot action, a bit like reversing a semi - road train? or a pulley system - look I don't know - only guessing ,-tell me -

July 4 2013 at 7 AM