Sunday, October 27, 2024

I had a question about leverage and mechanical advantage

 

 

Who do I turn to with such a question?  McKee.  He’s a design engineer so we know he’s well versed.  He’s also a sculptor, so we know whatever solution he proposes is going to be elegant.  This is the guy who has a motto emblazoned over an elaborate oak and stained-glass hobbit door on his house that reads: “Never make anything simple and efficient if a way can be found to make it complex and wonderful.”


 

Our problem had to do with the couch/bed in the van.  There is a certain lack of logic to how it functions.  It’s primarily a jackknife couch, with an additional stationary piece on one end.  To convert from a couch to a bed is easy.  Lift up in the front edge of the couch seat and the parts (couch seat and couch back) separate and lay down flat for a bed.  To reconstitute the couch, however, is not quite so easy.  With the whole thing laid out flat, the leverage is gone.  There is not enough advantage to just lift the front of the couch seat and have everything pop back into place.  It takes more power than I possess.  The combined effort of Judy and me together, lifting from the front, can get it done, but that didn’t feel sustainable as a long-term solution.

 

I thought about this for weeks and came up with a couple solutions myself that should have helped, but they didn’t.  So, I turned to McKee.  “Leverage and mechanical advantage” he said.  “I can deal with that.”  We drove to his house.  I demonstrated the difficulty.  I got the couch part-way up and left it in that position so he could examine the mechanism.  He took a long look from every angle.  He muttered.  He disappeared to his garage and came back out with an improvised tool.  He directed me to the leverage point on the frame.  “Stick this in there and lift up here.”  I did.  The front of the bed lifted right up, and the rest was easy.  Exactly the power assist we needed.  And here it is, the elegant solution.


 

A four-foot long 2x4 board.  (Sanded and rounded so we won’t get splinters.)  Elegant in its simplicity.  Stows on the floor slid-in next to the bed.

 

The McKees.  Such good friends for so many years (50).

 


 

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