[TowerTalk] Tram Rope/cable breakage
Cam and Juli Hedrick
walnutcreek at appstate.net
Tue Dec 19 21:55:29 EST 2006
By my experience any cable under load is very dangerous, more so than a
chain in that it is smaller diameter and will cut through objects.
Though I was Air Force I witnessed a cable break on a tank recovery vehicle
and cut a man in half.
When I am winching cable I tie rags to the cable and loop logging chains
over them in addition to being well out of the way with a remote control for
the winch. I used the 8k Warn on my truck in raising antennas and have not
hard a breakage, but then again I also install extra temporary guys on the
opposite side of the tower just in case of a failure. With the proper
pulley system you can decrease the load both on the cable and the system
thus increasing the safety margin for the crew.
Take a look at Z-Drag systems used in climbing and high angle rescue and use
the best pulley designed for cable you can obtain. My pulleys are for 7/16
wire rope and rated at 23k lbs. A block and tackle arrangement with cables
lowers the load at the winch and on the system, thus increasing safety.
I always winch directly at the tower with this arrangement I lower the
actual load on the tower by a factor of about 5.7.
Anytime you can lower the working load you increase the safety margin. If
you can lower the stresses on the tram system it is in your best interest.
I'm at the crane point at this QTH, so I've no tram system to worry with.
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