> First, definitions... A capstan is not a winch.
Perhaps, but Tower Jack calls it a "capstan electric winch". The
manufacturer, My-Te Products, calls it a "Capstan Winch-Hoist". In fact, the
web is full of references to capstan winches. Seems most of the
manufacturers call the device a capstan winch. I guess they're all using the
> Capstans are not man-rated in the
> occupational-safety world; i.e., they should never be used on
> a line that is supporting a person.
That's the first warning in the instructions. I have no plans for hauling
people up my tower!
However, the device is a godsend for building and rigging towers. I was able
to stack 110' of Rohn 55 (100 lbs per section) with the help of a single
person on the ground running the capstan (winch). We raised the top section
fully loaded, with top plate, two rotor shelves and the rotor. We could have
lifted it with the mast, too, had we spent the time to figure out how to
suspend that load (different balance point than a bare section.) The two of
us were able to tram the 40-2CD by ourselves as well. In addition to
eliminating a lot of grunting, and probably being safer than a big team of
people hauling on a rope, we didn't have the issue of trying to schedule 4-6
people every time the weather cleared enough to raise sections or antennas
(not easy here in rural New England.)
> A capstan (or winch) can be located away from the tower
> base; e.g., bolted to suitably anchored posts.
Installing anchored posts in my open field would have required a fair amount
of additional work. Bolting to the tower has been a simple solution.
Tramming has been the only application where the capstan operator has been
directly under the load, and then only for a brief time.
> turning pulley near the base of the tower, and then
Isn't this known as a "snatch block"?
> Wire clips of correct size, number, spacing and
> installation (nuts tensioned according to manufacturer's
> instructions) will have greater holding strength than the
> breaking strength of the wire cable.
Where is the published data on that? Where is the information on proper
torque for tightening the nuts on, say, 1/4" wire clips?
> I'd feel comfortable using a guy grip on 7-strand steel
> cable tram line, since that's what it was designed for.
I don't doubt that, but take a look at the Preform website. The literature
for dead-end guy grips doesn't say anything about 7-strand steel cable. The
only spec is the cable diameter. Now, the word "cable" is used, not rope or
wire rope, so perhaps that's enough to rule out wire rope. But they don't
specify the number of strands.
> I don't know how the
> manufacturer feels about using a guy grip designed for
> 7-strand cable on wire rope of the same diameter; the
> manufacturer's Prime Directive applies here. Maybe there are
> grips designed specifically for wire rope.
My wire rope happens to be 7-strand as well, though of course it's 7x19.
It's clearly softer than EHS, which may very well make it unsuitable for use
with guy grips. Does anyone know?
73, Dick WC1M
> -- Eric
> on 06 Dec 19 Tue 18:34 Dick Green WC1M said the following:
> >> Alternately, use an electric winch with a long cord to the
> >> control buttons, so the operator can stand well clear of the
> >> work zone.
> > I have an electric capstan winch (the TowerJack model)
> bolted to the tower
> > at the base. The capstan requires the operator to pull the
> excess rope off
> > the drum in pretty much a straight line from the tower --
> right under the
> > tram. I guess the way around that would be to put a pulley
> on the tie-off
> > post (I planted a 4x4 about 20' from the tower for that),
> and take the rope
> > off at 90-degrees to the tram. I'd have to add about 30
> feet of wire to the
> > foot switch -- it only has a 10 foot cord now.
> > Still have the problem of the person operating the tiller.
> You have to be
> > under the antenna for that.
> >> Properly installed wire rope clips are fine, as is a properly
> >> installed Nicropress compression fitting.
> > Probably the subject of another thread, but my
> understanding is that there's
> > no way to determine the load rating of a wire rope clip connection.
> > Apparently, there are no published load ratings. Of course,
> the Rohn catalog
> > shows wire rope clips as a method for terminating guy
> wires, so perhaps
> > their engineers have the data.
> > A guy grip is a lot cheaper than a Nicopress tool. Any
> reason not to use a
> > guy grip?
> >> I would a wire rope clip at the bottom, rather than rely on
> >> the Klein grip during the job. That reduces the number of
> >> potential failure points.
> > I can't agree with that. Klein grips are designed for much
> heavier loads
> > than we're talking about. My gosh, many of us routinely use
> them to tension
> > our guy wires to 500-1000 lbs or more. If they're not safe
> for tramming,
> > they're not safe for tensioning guys. Further, my feeling
> is that a Klein
> > grip does a lot less damage to the wire rope than a clip.
> > Now... Please don't flame me with a bunch of claims in
> defense of wire rope
> > clips. I'm not saying they don't work. But I and concerned
> about the lack of
> > published load ratings. Also, I've seen wire rope slip when
> the clips aren't
> > tightened properly.
> > 73, Dick WC1M
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