Are you referring to the winch being used to tilt the tower over or to raise
the tower when it is in vertical position? If the latter then the winch
cable is always loading the winch and would not operate in free wheel as
mine does when tilting the tower up or down.
This morning I went to both of my towers (one is horizontal now and the
other is vertical). I observed the pawl and pawl gear. As Alan mentions,
the pawl gear rotates and pawl bobs in and out as the winch cable is being
wound in but does not when the winch cable is being let out. I did not see
any lateral (along the axis) movement of the pawl gear. I surmise that the
purpose of the spring is to bring the pawl back out as the pawl gear rotates
between teeth.
After cranking the winch to make the cable taut and then reversing to play
out the cable, the braking mechanism is operating which requires force on
the handle to overcome the braking. As the cable becomes less taught the
braking mechanism applies less and less force and shortly gravity on the
winch handle is enough to overcome any residual braking that is still in
operation. As mentioned the pawl gear and pawl is not operating during the
cable let out.
I will appreciate if anyone can explain how the braking mechanism actually
works to decrease the braking pressure on the pads when the load on the
winch is decreased?
I write these lengthy postings to alert readers that the Fulton k1550 and
k2550 definitely can get into a free wheeling mode without a winch failure.
It appears that if one goes from a taut (loaded) winch directly to let out
the cable the winch braking mechanism will hold the tower without the handle
being held. However if the winch cable is slack (unloaded) and the tower is
moved to begin its lowering (tilt) the braking mechanism will not be
operating and the tower can crash to the ground.
When preparing to tilt the tower back down, be sure to crank the winch until
the cable is taut. Then when pulling on the handle to let out the cable to
lower the tower be sure to notice that it requires considerable force on the
winch handle to move it. Then it is safe (probably) to move the tower into
a falling position.
k7puc
----- Original Message -----
From: "Alan NV8A" <nv8a@att.net>
To: "towertalk reflector" <towertalk@contesting.com>
Cc: "Al Williams" <alwilliams@olywa.net>
Sent: Monday, March 19, 2007 7:49 AM
Subject: Re: [TowerTalk] Tower winch failure
> When I examined the winch on my HDX-555, it seemed that the brake
> mechanism applied permanent friction between the shaft and the toothed
> wheel, but when the cable was being wound in the pawl allowed that toothed
> wheel to turn freely. When the cable was being let out, the spring-loaded
> pawl prevented the toothed wheel from turning, the friction being
> sufficient to prevent free-wheeling and in fact requiring considerable
> effort let the cable out and lower the tower.
>
> AFAICS, the only way it can free-wheel is if something moves out of
> alignment or if the pawl fails to engage the toothed wheel due to spring
> failure or lack of lubrication of the pivot.
snip
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