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Guillotining your family is bad, mkay.

March 12th, 2009

So the Thern 472 winch that I was  using to lift the camper top has an unfortunate bug.    The winch is a worm drive winch.    Typically worm drives don’t (or are very difficult) to drive from the output shaft.    This acts as a natural brake.    When lowering the roof,  if the drill slips off the drive nut, the roof can continue to fall at an alarming rate.    If someone happened to be inside standing up, they would certainly suffer spinal injuries.   And if they had a head one of the windows in the canvas it would sever said head.    Not good.

Thern makes winches that are good for lifting that have a brake to prevent run-away drops.    The 4622-PB winch:


This is a smaller winch and the winch drum is a too small for the ropes to fit in one wrap.     So I disassembled it and extended the drum with some pipe turned on the lathe and welded in a new section to the frame.



I could have removed the brake and mounted that on the old winch, but it was secured to the input shaft with a set-pin that I could not for the life of me punch out.    Also there are a few clearance issues with the lift poles that I would have had to figure out as well.

Once the roof is raised, I will have some Kwik-Lok pins which will pin thru holes in the lift poles and guide tubes to secure the roof and prevent it from falling in the unlikely event of a rope or pulley breaking.


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