"Doordoc" wrote in message
om...
Peter R. wrote in message
...
G.R. Patterson III wrote:
Garage door openers drive a sprocket that operates a circular chain.
Some of the
older units had a block on the chain that tripped a switch when the
door was raised.
This block could be adjusted to fine-tune the system. My Genie units
do not have
this. I assume (but do not know) that they simply pull the chain for a
fixed distance
(most doors are 7' tall).
So. Measure the distance you have to pull your chain to open the
hangar door. Work
out the ratio between that and 7'. Rig a reduction gear out of two
appropriately
sized pulleys and a belt and drive that from a chain driven by a
garage door opener.
You can probably use your existing chain pulley as one pulley in the
reduction gear
and mount the whole thing high on the wall.
Thanks, George. I might just try this project.
Actually many residential garage doors will open up a 10' high door
when they have the right length rail & chain. So if your door is 10'
tall you do not need to change the reduction at all, but if your door
is taller then 10' you would have to change the reduction. However if
you change the reduction very much (depends on door height) you are
also going to increase the speed that the door opens which may result
in an unsafe operating condition & is also going to put more wear &
tear on the door. Residential garage door openers are not designed for
this type of use & for your own safety is not something I would
personally recommend doing.
Doordoc
I would say, that a proper application of a residential opener could be
safe, and reliable. It would take some doing.
Gear the output of the opener, so that the door moves at a speed comparable
to how fast the door would move, if it were being opened manually. This
would mean a much longer cycle time than the electric opener was designed
for, so the original limit switches would not work. A Craftsman (Sears)
opener, of older design had built in limit switches run by a threaded rod,
to control the start and stop locations, and thus times. Keep the concept,
but instead of pushing the switches using the built in threaded rod,
relocate new switches, so the doors physically push on the new switches to
start, stop, and reverse the movement.
I have my show sawdust system run by an old opener. The only parts I had to
buy were two new limit switches, and a bit of wire. The two new switches
are actuated by the threaded rod, but the original switches still start and
stop the opener. The new switches hold in the coil for the magnetic starter
circuit, and still let the pushbutton stations operate normally when the
remote is not being used.
Good luck. Contact me, if you want to make a go at it. I do happen to have
one more old opener on hand, :-))
--
Jim in NC
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