On 4/4/2014 12:26 PM, ftravanty wrote:
The only type of hand winch I would trust is one like a Fulton 1500 or
2500 that has a self actuating brake, and is in good working
condition. A winch with a re moveable handle which is part of the self
actuating brake, or one that can free wheel, being held by muscle
power, can be very dangerous for tower work.
I like the latch on mine and other than a lapse in judgement feel it's
quite safe. Going up or down, the latch only lets you go in one
direction and if you let go, it can't freewheel. Noisy, but adds little
friction to the work.
I'd like to get a worm gear drive and convert it to a real worm gear,
worm gear wheel type drive. They take very little effort on the crank,
but the gear ratio is such that it can't freewheel when the driving
force is applied from the output end. I think it'd be worth the extra money.
A single flute worm with a 20 tooth worm gear wheel would have a 20:1
ratio, while a 2 flute worm would have a 10:1 ratio with the same size
worm gear wheel. The conversion is fairly simple as you only need a worm
gear wheel of the right diameter and pitch which should be the same # of
teeth you have in the original setup. They do need a fairly rigid
mount. (no play in the gears and they should be fully meshed).
If you really want to know if it will be self locking it "depends on
the lead angle, the pressure angle, and the coefficient of friction;
however, it is approximately correct to say that a worm and gear will be
self-locking if the tangent of the lead angle is less than the
coefficient of friction." (Wikipedia) <:-))
73
Roger (K8RI)
Frank W9JCC
On 4/4/2014 11:00 AM, towertalk-request@contesting.com wrote:
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