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[TowerTalk] Worm gear winch

To: towertalk@contesting.com
Subject: [TowerTalk] Worm gear winch
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
Date: Fri, 04 Apr 2014 14:13:59 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
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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