I “invented” (kinda plagiarized) the use of an ordinary boat-lift to operate my hangar door of my own design. The door operates similarly to an old-style garage door in that as it raises up...it also rotates to the horizontal position.
(Most airplane hangar doors are “bi-fold” and operate in a folding method like closing an open book...the problem with them is they lose a lot of headroom and they cannot be left open when it’s windy or they’ll collapse on themselves. I didn’t want either to be a limitation... this design is captured in tracks on each end and can be left open in any wind...and acts like an awning when partially open.)
Well, anyway, it is lifted by an ordinary boat-lift which operates cables thru pulleys/sheaves and therefore places very little stress on the bldg since the cables are directly opposing each other. An advantage is that any failure simply “freezes” the door. It’s much safer than commercial designs in that respect.
The DOWN-side is that when the boat-lift fails the door “freezes”...as designed. I’ve never had to deal with this in the 20 years since I built it.
Until today. I went to bed last night and as I left the hangar I hit the “down” switch, flipped off the lights and exited the personell-door and went to bed leaving the overhead door to close and shut itself off.... or so I thought.
This morning I discovered the door still in the half-open position and the motor spinning with the V-belt apparently burned-thru.
My problem is: How do I get up there and replace the V-belt with the door half-open/half-closed? Simple, I thought.... put the extension ladder against the door and walk upon the door itself to get to the boat lift to change the belt.
BUT... the BELT was not the problem! The problem was the worm-and-ring gear were frozen. To remove/separate them would allow the door to FALL to the ground!
After another cup of coffee I decided to slightlhy LIFT the door with the FEL to relieve the load from the cables, repair/replace the worm/ring gears while the FEL held the door in-situ. TA-DA! KUBOTA TO THE RESCUE!
Turns out, that the problem was seen to be only a lubrication problem AND a fresh V-Belt after the FEL relieved the load from the lift-assy and the friction could be detected without the load of the door.
This could have been very hazardous if the door had fallen while I stood on it, but the FEL as back-up gave a secondary-support. (I know, I know...it was only backup and as a method of diagnosis to get the load off the cables.)
